feat: migrate from Cedar to SpiceDB authorization system

This is a major architectural change that replaces the Cedar policy-based
authorization system with SpiceDB's relation-based authorization.

Key changes:

- Migrate from Rust to Go implementation
- Replace Cedar policies with SpiceDB schema and relationships
- Switch from envoy `ext_authz` with Cedar to SpiceDB permission checks
- Update build system and dependencies for Go ecosystem
- Maintain Envoy integration for external authorization

This change enables more flexible permission modeling through SpiceDB's
Google Zanzibar inspired relation-based system, supporting complex
hierarchical permissions that were difficult to express in Cedar.

Breaking change: Existing Cedar policies and Rust-based configuration
will no longer work and need to be migrated to SpiceDB schema.

1 files changed, 0 insertions, 3305 deletions

diff --git a/vendor/socket2/src/sys/unix.rs b/vendor/socket2/src/sys/unix.rs
deleted file mode 100644
index fbe4cc3a..00000000
--- a/vendor/socket2/src/sys/unix.rs
+++ /dev/null
@@ -1,3305 +0,0 @@
-// Copyright 2015 The Rust Project Developers.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-use std::cmp::min;
-use std::ffi::OsStr;
-#[cfg(not(target_os = "redox"))]
-use std::io::IoSlice;
-use std::marker::PhantomData;
-use std::mem::{self, size_of, MaybeUninit};
-use std::net::Shutdown;
-use std::net::{Ipv4Addr, Ipv6Addr};
-#[cfg(all(
-    feature = "all",
-    any(
-        target_os = "ios",
-        target_os = "visionos",
-        target_os = "macos",
-        target_os = "tvos",
-        target_os = "watchos",
-        target_os = "illumos",
-        target_os = "solaris",
-    )
-))]
-use std::num::NonZeroU32;
-#[cfg(all(
-    feature = "all",
-    any(
-        target_os = "aix",
-        target_os = "android",
-        target_os = "freebsd",
-        target_os = "ios",
-        target_os = "visionos",
-        target_os = "linux",
-        target_os = "macos",
-        target_os = "tvos",
-        target_os = "watchos",
-    )
-))]
-use std::num::NonZeroUsize;
-use std::os::unix::ffi::OsStrExt;
-#[cfg(all(
-    feature = "all",
-    any(
-        target_os = "aix",
-        target_os = "android",
-        target_os = "freebsd",
-        target_os = "ios",
-        target_os = "visionos",
-        target_os = "linux",
-        target_os = "macos",
-        target_os = "tvos",
-        target_os = "watchos",
-    )
-))]
-use std::os::unix::io::RawFd;
-use std::os::unix::io::{AsFd, AsRawFd, BorrowedFd, FromRawFd, IntoRawFd, OwnedFd};
-#[cfg(feature = "all")]
-use std::os::unix::net::{UnixDatagram, UnixListener, UnixStream};
-use std::path::Path;
-use std::ptr;
-use std::time::{Duration, Instant};
-use std::{io, slice};
-
-#[cfg(not(any(
-    target_os = "ios",
-    target_os = "visionos",
-    target_os = "macos",
-    target_os = "tvos",
-    target_os = "watchos",
-    target_os = "cygwin",
-)))]
-use libc::ssize_t;
-use libc::{in6_addr, in_addr};
-
-use crate::{Domain, Protocol, SockAddr, TcpKeepalive, Type};
-#[cfg(not(target_os = "redox"))]
-use crate::{MsgHdr, MsgHdrMut, RecvFlags};
-
-pub(crate) use libc::c_int;
-
-// Used in `Domain`.
-pub(crate) use libc::{AF_INET, AF_INET6, AF_UNIX};
-// Used in `Type`.
-#[cfg(all(feature = "all", target_os = "linux"))]
-pub(crate) use libc::SOCK_DCCP;
-#[cfg(all(feature = "all", not(any(target_os = "redox", target_os = "espidf"))))]
-pub(crate) use libc::SOCK_RAW;
-#[cfg(all(feature = "all", not(target_os = "espidf")))]
-pub(crate) use libc::SOCK_SEQPACKET;
-pub(crate) use libc::{SOCK_DGRAM, SOCK_STREAM};
-// Used in `Protocol`.
-#[cfg(all(feature = "all", target_os = "linux"))]
-pub(crate) use libc::IPPROTO_DCCP;
-#[cfg(target_os = "linux")]
-pub(crate) use libc::IPPROTO_MPTCP;
-#[cfg(all(feature = "all", any(target_os = "freebsd", target_os = "linux")))]
-pub(crate) use libc::IPPROTO_SCTP;
-#[cfg(all(
-    feature = "all",
-    any(
-        target_os = "android",
-        target_os = "freebsd",
-        target_os = "fuchsia",
-        target_os = "linux",
-    )
-))]
-pub(crate) use libc::IPPROTO_UDPLITE;
-pub(crate) use libc::{IPPROTO_ICMP, IPPROTO_ICMPV6, IPPROTO_TCP, IPPROTO_UDP};
-// Used in `SockAddr`.
-#[cfg(all(feature = "all", any(target_os = "freebsd", target_os = "openbsd")))]
-pub(crate) use libc::IPPROTO_DIVERT;
-pub(crate) use libc::{
-    sa_family_t, sockaddr, sockaddr_in, sockaddr_in6, sockaddr_storage, socklen_t,
-};
-// Used in `RecvFlags`.
-#[cfg(not(any(target_os = "redox", target_os = "espidf")))]
-pub(crate) use libc::MSG_TRUNC;
-#[cfg(not(target_os = "redox"))]
-pub(crate) use libc::SO_OOBINLINE;
-// Used in `Socket`.
-#[cfg(not(target_os = "nto"))]
-pub(crate) use libc::ipv6_mreq as Ipv6Mreq;
-#[cfg(all(
-    feature = "all",
-    not(any(
-        target_os = "dragonfly",
-        target_os = "fuchsia",
-        target_os = "hurd",
-        target_os = "illumos",
-        target_os = "netbsd",
-        target_os = "openbsd",
-        target_os = "redox",
-        target_os = "solaris",
-        target_os = "haiku",
-        target_os = "espidf",
-        target_os = "vita",
-        target_os = "cygwin",
-    ))
-))]
-pub(crate) use libc::IPV6_RECVHOPLIMIT;
-#[cfg(not(any(
-    target_os = "dragonfly",
-    target_os = "fuchsia",
-    target_os = "hurd",
-    target_os = "illumos",
-    target_os = "netbsd",
-    target_os = "openbsd",
-    target_os = "redox",
-    target_os = "solaris",
-    target_os = "haiku",
-    target_os = "espidf",
-    target_os = "vita",
-)))]
-pub(crate) use libc::IPV6_RECVTCLASS;
-#[cfg(all(feature = "all", not(any(target_os = "redox", target_os = "espidf"))))]
-pub(crate) use libc::IP_HDRINCL;
-#[cfg(not(any(
-    target_os = "aix",
-    target_os = "dragonfly",
-    target_os = "fuchsia",
-    target_os = "illumos",
-    target_os = "netbsd",
-    target_os = "openbsd",
-    target_os = "redox",
-    target_os = "solaris",
-    target_os = "haiku",
-    target_os = "hurd",
-    target_os = "nto",
-    target_os = "espidf",
-    target_os = "vita",
-    target_os = "cygwin",
-)))]
-pub(crate) use libc::IP_RECVTOS;
-#[cfg(not(any(
-    target_os = "fuchsia",
-    target_os = "redox",
-    target_os = "solaris",
-    target_os = "haiku",
-    target_os = "illumos",
-)))]
-pub(crate) use libc::IP_TOS;
-#[cfg(not(any(
-    target_os = "ios",
-    target_os = "visionos",
-    target_os = "macos",
-    target_os = "tvos",
-    target_os = "watchos",
-)))]
-pub(crate) use libc::SO_LINGER;
-#[cfg(any(
-    target_os = "ios",
-    target_os = "visionos",
-    target_os = "macos",
-    target_os = "tvos",
-    target_os = "watchos",
-))]
-pub(crate) use libc::SO_LINGER_SEC as SO_LINGER;
-#[cfg(any(target_os = "linux", target_os = "cygwin"))]
-pub(crate) use libc::SO_PASSCRED;
-pub(crate) use libc::{
-    ip_mreq as IpMreq, linger, IPPROTO_IP, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, IPV6_MULTICAST_IF,
-    IPV6_MULTICAST_LOOP, IPV6_UNICAST_HOPS, IPV6_V6ONLY, IP_ADD_MEMBERSHIP, IP_DROP_MEMBERSHIP,
-    IP_MULTICAST_IF, IP_MULTICAST_LOOP, IP_MULTICAST_TTL, IP_TTL, MSG_OOB, MSG_PEEK, SOL_SOCKET,
-    SO_BROADCAST, SO_ERROR, SO_KEEPALIVE, SO_RCVBUF, SO_RCVTIMEO, SO_REUSEADDR, SO_SNDBUF,
-    SO_SNDTIMEO, SO_TYPE, TCP_NODELAY,
-};
-#[cfg(not(any(
-    target_os = "dragonfly",
-    target_os = "haiku",
-    target_os = "hurd",
-    target_os = "netbsd",
-    target_os = "openbsd",
-    target_os = "redox",
-    target_os = "fuchsia",
-    target_os = "nto",
-    target_os = "espidf",
-    target_os = "vita",
-)))]
-pub(crate) use libc::{
-    ip_mreq_source as IpMreqSource, IP_ADD_SOURCE_MEMBERSHIP, IP_DROP_SOURCE_MEMBERSHIP,
-};
-#[cfg(not(any(
-    target_os = "dragonfly",
-    target_os = "freebsd",
-    target_os = "haiku",
-    target_os = "illumos",
-    target_os = "ios",
-    target_os = "visionos",
-    target_os = "macos",
-    target_os = "netbsd",
-    target_os = "nto",
-    target_os = "openbsd",
-    target_os = "solaris",
-    target_os = "tvos",
-    target_os = "watchos",
-)))]
-pub(crate) use libc::{IPV6_ADD_MEMBERSHIP, IPV6_DROP_MEMBERSHIP};
-#[cfg(any(
-    target_os = "dragonfly",
-    target_os = "freebsd",
-    target_os = "haiku",
-    target_os = "illumos",
-    target_os = "ios",
-    target_os = "visionos",
-    target_os = "macos",
-    target_os = "netbsd",
-    target_os = "openbsd",
-    target_os = "solaris",
-    target_os = "tvos",
-    target_os = "watchos",
-))]
-pub(crate) use libc::{
-    IPV6_JOIN_GROUP as IPV6_ADD_MEMBERSHIP, IPV6_LEAVE_GROUP as IPV6_DROP_MEMBERSHIP,
-};
-#[cfg(all(
-    feature = "all",
-    any(
-        target_os = "android",
-        target_os = "dragonfly",
-        target_os = "freebsd",
-        target_os = "fuchsia",
-        target_os = "illumos",
-        target_os = "ios",
-        target_os = "visionos",
-        target_os = "linux",
-        target_os = "macos",
-        target_os = "netbsd",
-        target_os = "tvos",
-        target_os = "watchos",
-        target_os = "cygwin",
-    )
-))]
-pub(crate) use libc::{TCP_KEEPCNT, TCP_KEEPINTVL};
-
-// See this type in the Windows file.
-pub(crate) type Bool = c_int;
-
-#[cfg(any(
-    target_os = "ios",
-    target_os = "visionos",
-    target_os = "macos",
-    target_os = "nto",
-    target_os = "tvos",
-    target_os = "watchos",
-))]
-use libc::TCP_KEEPALIVE as KEEPALIVE_TIME;
-#[cfg(not(any(
-    target_os = "haiku",
-    target_os = "ios",
-    target_os = "visionos",
-    target_os = "macos",
-    target_os = "nto",
-    target_os = "openbsd",
-    target_os = "tvos",
-    target_os = "watchos",
-    target_os = "vita",
-)))]
-use libc::TCP_KEEPIDLE as KEEPALIVE_TIME;
-
-/// Helper macro to execute a system call that returns an `io::Result`.
-macro_rules! syscall {
-    ($fn: ident ( $($arg: expr),* $(,)* ) ) => {{
-        #[allow(unused_unsafe)]
-        let res = unsafe { libc::$fn($($arg, )*) };
-        if res == -1 {
-            Err(std::io::Error::last_os_error())
-        } else {
-            Ok(res)
-        }
-    }};
-}
-
-/// Maximum size of a buffer passed to system call like `recv` and `send`.
-#[cfg(not(any(
-    target_os = "ios",
-    target_os = "visionos",
-    target_os = "macos",
-    target_os = "tvos",
-    target_os = "watchos",
-    target_os = "cygwin",
-)))]
-const MAX_BUF_LEN: usize = ssize_t::MAX as usize;
-
-// The maximum read limit on most posix-like systems is `SSIZE_MAX`, with the
-// man page quoting that if the count of bytes to read is greater than
-// `SSIZE_MAX` the result is "unspecified".
-//
-// On macOS, however, apparently the 64-bit libc is either buggy or
-// intentionally showing odd behavior by rejecting any read with a size larger
-// than or equal to INT_MAX. To handle both of these the read size is capped on
-// both platforms.
-#[cfg(any(
-    target_os = "ios",
-    target_os = "visionos",
-    target_os = "macos",
-    target_os = "tvos",
-    target_os = "watchos",
-    target_os = "cygwin",
-))]
-const MAX_BUF_LEN: usize = c_int::MAX as usize - 1;
-
-// TCP_CA_NAME_MAX isn't defined in user space include files(not in libc)
-#[cfg(all(feature = "all", any(target_os = "freebsd", target_os = "linux")))]
-const TCP_CA_NAME_MAX: usize = 16;
-
-#[cfg(any(
-    all(
-        target_os = "linux",
-        any(
-            target_env = "gnu",
-            all(target_env = "uclibc", target_pointer_width = "64")
-        )
-    ),
-    target_os = "android",
-))]
-type IovLen = usize;
-
-#[cfg(any(
-    all(
-        target_os = "linux",
-        any(
-            target_env = "musl",
-            target_env = "ohos",
-            all(target_env = "uclibc", target_pointer_width = "32")
-        )
-    ),
-    target_os = "aix",
-    target_os = "dragonfly",
-    target_os = "freebsd",
-    target_os = "fuchsia",
-    target_os = "haiku",
-    target_os = "hurd",
-    target_os = "illumos",
-    target_os = "ios",
-    target_os = "visionos",
-    target_os = "macos",
-    target_os = "netbsd",
-    target_os = "nto",
-    target_os = "openbsd",
-    target_os = "solaris",
-    target_os = "tvos",
-    target_os = "watchos",
-    target_os = "espidf",
-    target_os = "vita",
-    target_os = "cygwin",
-))]
-type IovLen = c_int;
-
-/// Unix only API.
-impl Domain {
-    /// Domain for low-level packet interface, corresponding to `AF_PACKET`.
-    #[cfg(all(
-        feature = "all",
-        any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-        )))
-    )]
-    pub const PACKET: Domain = Domain(libc::AF_PACKET);
-
-    /// Domain for low-level VSOCK interface, corresponding to `AF_VSOCK`.
-    #[cfg(all(feature = "all", any(target_os = "android", target_os = "linux")))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(feature = "all", any(target_os = "android", target_os = "linux"))))
-    )]
-    pub const VSOCK: Domain = Domain(libc::AF_VSOCK);
-}
-
-impl_debug!(
-    Domain,
-    libc::AF_INET,
-    libc::AF_INET6,
-    libc::AF_UNIX,
-    #[cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux"))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux")))
-    )]
-    libc::AF_PACKET,
-    #[cfg(any(target_os = "android", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(any(target_os = "android", target_os = "linux"))))]
-    libc::AF_VSOCK,
-    libc::AF_UNSPEC, // = 0.
-);
-
-/// Unix only API.
-impl Type {
-    /// Set `SOCK_NONBLOCK` on the `Type`.
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "android",
-            target_os = "dragonfly",
-            target_os = "freebsd",
-            target_os = "fuchsia",
-            target_os = "illumos",
-            target_os = "linux",
-            target_os = "netbsd",
-            target_os = "openbsd",
-            target_os = "cygwin",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "android",
-                target_os = "dragonfly",
-                target_os = "freebsd",
-                target_os = "fuchsia",
-                target_os = "illumos",
-                target_os = "linux",
-                target_os = "netbsd",
-                target_os = "openbsd"
-            )
-        )))
-    )]
-    pub const fn nonblocking(self) -> Type {
-        Type(self.0 | libc::SOCK_NONBLOCK)
-    }
-
-    /// Set `SOCK_CLOEXEC` on the `Type`.
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "android",
-            target_os = "dragonfly",
-            target_os = "freebsd",
-            target_os = "fuchsia",
-            target_os = "hurd",
-            target_os = "illumos",
-            target_os = "linux",
-            target_os = "netbsd",
-            target_os = "openbsd",
-            target_os = "redox",
-            target_os = "solaris",
-            target_os = "cygwin",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "android",
-                target_os = "dragonfly",
-                target_os = "freebsd",
-                target_os = "fuchsia",
-                target_os = "hurd",
-                target_os = "illumos",
-                target_os = "linux",
-                target_os = "netbsd",
-                target_os = "openbsd",
-                target_os = "redox",
-                target_os = "solaris",
-            )
-        )))
-    )]
-    pub const fn cloexec(self) -> Type {
-        self._cloexec()
-    }
-
-    #[cfg(any(
-        target_os = "android",
-        target_os = "dragonfly",
-        target_os = "freebsd",
-        target_os = "fuchsia",
-        target_os = "hurd",
-        target_os = "illumos",
-        target_os = "linux",
-        target_os = "netbsd",
-        target_os = "openbsd",
-        target_os = "redox",
-        target_os = "solaris",
-        target_os = "cygwin",
-    ))]
-    pub(crate) const fn _cloexec(self) -> Type {
-        Type(self.0 | libc::SOCK_CLOEXEC)
-    }
-}
-
-impl_debug!(
-    Type,
-    libc::SOCK_STREAM,
-    libc::SOCK_DGRAM,
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    libc::SOCK_DCCP,
-    #[cfg(not(any(target_os = "redox", target_os = "espidf")))]
-    libc::SOCK_RAW,
-    #[cfg(not(any(target_os = "redox", target_os = "haiku", target_os = "espidf")))]
-    libc::SOCK_RDM,
-    #[cfg(not(target_os = "espidf"))]
-    libc::SOCK_SEQPACKET,
-    /* TODO: add these optional bit OR-ed flags:
-    #[cfg(any(
-        target_os = "android",
-        target_os = "dragonfly",
-        target_os = "freebsd",
-        target_os = "fuchsia",
-        target_os = "linux",
-        target_os = "netbsd",
-        target_os = "openbsd"
-    ))]
-    libc::SOCK_NONBLOCK,
-    #[cfg(any(
-        target_os = "android",
-        target_os = "dragonfly",
-        target_os = "freebsd",
-        target_os = "fuchsia",
-        target_os = "linux",
-        target_os = "netbsd",
-        target_os = "openbsd"
-    ))]
-    libc::SOCK_CLOEXEC,
-    */
-);
-
-impl_debug!(
-    Protocol,
-    libc::IPPROTO_ICMP,
-    libc::IPPROTO_ICMPV6,
-    libc::IPPROTO_TCP,
-    libc::IPPROTO_UDP,
-    #[cfg(target_os = "linux")]
-    libc::IPPROTO_MPTCP,
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    libc::IPPROTO_DCCP,
-    #[cfg(all(feature = "all", any(target_os = "freebsd", target_os = "linux")))]
-    libc::IPPROTO_SCTP,
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "android",
-            target_os = "freebsd",
-            target_os = "fuchsia",
-            target_os = "linux",
-        )
-    ))]
-    libc::IPPROTO_UDPLITE,
-    #[cfg(all(feature = "all", any(target_os = "freebsd", target_os = "openbsd")))]
-    libc::IPPROTO_DIVERT,
-);
-
-/// Unix-only API.
-#[cfg(not(target_os = "redox"))]
-impl RecvFlags {
-    /// Check if the message terminates a record.
-    ///
-    /// Not all socket types support the notion of records. For socket types
-    /// that do support it (such as [`SEQPACKET`]), a record is terminated by
-    /// sending a message with the end-of-record flag set.
-    ///
-    /// On Unix this corresponds to the `MSG_EOR` flag.
-    ///
-    /// [`SEQPACKET`]: Type::SEQPACKET
-    #[cfg(not(target_os = "espidf"))]
-    pub const fn is_end_of_record(self) -> bool {
-        self.0 & libc::MSG_EOR != 0
-    }
-
-    /// Check if the message contains out-of-band data.
-    ///
-    /// This is useful for protocols where you receive out-of-band data
-    /// mixed in with the normal data stream.
-    ///
-    /// On Unix this corresponds to the `MSG_OOB` flag.
-    pub const fn is_out_of_band(self) -> bool {
-        self.0 & libc::MSG_OOB != 0
-    }
-
-    /// Check if the confirm flag is set.
-    ///
-    /// This is used by SocketCAN to indicate a frame was sent via the
-    /// socket it is received on. This flag can be interpreted as a
-    /// 'transmission confirmation'.
-    ///
-    /// On Unix this corresponds to the `MSG_CONFIRM` flag.
-    #[cfg(all(feature = "all", any(target_os = "android", target_os = "linux")))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(feature = "all", any(target_os = "android", target_os = "linux"))))
-    )]
-    pub const fn is_confirm(self) -> bool {
-        self.0 & libc::MSG_CONFIRM != 0
-    }
-
-    /// Check if the don't route flag is set.
-    ///
-    /// This is used by SocketCAN to indicate a frame was created
-    /// on the local host.
-    ///
-    /// On Unix this corresponds to the `MSG_DONTROUTE` flag.
-    #[cfg(all(
-        feature = "all",
-        any(target_os = "android", target_os = "linux", target_os = "cygwin"),
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(target_os = "android", target_os = "linux", target_os = "cygwin")
-        )))
-    )]
-    pub const fn is_dontroute(self) -> bool {
-        self.0 & libc::MSG_DONTROUTE != 0
-    }
-}
-
-#[cfg(not(target_os = "redox"))]
-impl std::fmt::Debug for RecvFlags {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        let mut s = f.debug_struct("RecvFlags");
-        #[cfg(not(target_os = "espidf"))]
-        s.field("is_end_of_record", &self.is_end_of_record());
-        s.field("is_out_of_band", &self.is_out_of_band());
-        #[cfg(not(target_os = "espidf"))]
-        s.field("is_truncated", &self.is_truncated());
-        #[cfg(all(feature = "all", any(target_os = "android", target_os = "linux")))]
-        s.field("is_confirm", &self.is_confirm());
-        #[cfg(all(
-            feature = "all",
-            any(target_os = "android", target_os = "linux", target_os = "cygwin"),
-        ))]
-        s.field("is_dontroute", &self.is_dontroute());
-        s.finish()
-    }
-}
-
-#[repr(transparent)]
-pub struct MaybeUninitSlice<'a> {
-    vec: libc::iovec,
-    _lifetime: PhantomData<&'a mut [MaybeUninit<u8>]>,
-}
-
-unsafe impl<'a> Send for MaybeUninitSlice<'a> {}
-
-unsafe impl<'a> Sync for MaybeUninitSlice<'a> {}
-
-impl<'a> MaybeUninitSlice<'a> {
-    pub(crate) fn new(buf: &'a mut [MaybeUninit<u8>]) -> MaybeUninitSlice<'a> {
-        MaybeUninitSlice {
-            vec: libc::iovec {
-                iov_base: buf.as_mut_ptr().cast(),
-                iov_len: buf.len(),
-            },
-            _lifetime: PhantomData,
-        }
-    }
-
-    pub(crate) fn as_slice(&self) -> &[MaybeUninit<u8>] {
-        unsafe { slice::from_raw_parts(self.vec.iov_base.cast(), self.vec.iov_len) }
-    }
-
-    pub(crate) fn as_mut_slice(&mut self) -> &mut [MaybeUninit<u8>] {
-        unsafe { slice::from_raw_parts_mut(self.vec.iov_base.cast(), self.vec.iov_len) }
-    }
-}
-
-/// Returns the offset of the `sun_path` member of the passed unix socket address.
-pub(crate) fn offset_of_path(storage: &libc::sockaddr_un) -> usize {
-    let base = storage as *const _ as usize;
-    let path = ptr::addr_of!(storage.sun_path) as usize;
-    path - base
-}
-
-#[allow(unsafe_op_in_unsafe_fn)]
-pub(crate) fn unix_sockaddr(path: &Path) -> io::Result<SockAddr> {
-    // SAFETY: a `sockaddr_storage` of all zeros is valid.
-    let mut storage = unsafe { mem::zeroed::<sockaddr_storage>() };
-    let len = {
-        let storage = unsafe { &mut *ptr::addr_of_mut!(storage).cast::<libc::sockaddr_un>() };
-
-        let bytes = path.as_os_str().as_bytes();
-        let too_long = match bytes.first() {
-            None => false,
-            // linux abstract namespaces aren't null-terminated
-            Some(&0) => bytes.len() > storage.sun_path.len(),
-            Some(_) => bytes.len() >= storage.sun_path.len(),
-        };
-        if too_long {
-            return Err(io::Error::new(
-                io::ErrorKind::InvalidInput,
-                "path must be shorter than SUN_LEN",
-            ));
-        }
-
-        storage.sun_family = libc::AF_UNIX as sa_family_t;
-        // SAFETY: `bytes` and `addr.sun_path` are not overlapping and
-        // both point to valid memory.
-        // `storage` was initialized to zero above, so the path is
-        // already NULL terminated.
-        unsafe {
-            ptr::copy_nonoverlapping(
-                bytes.as_ptr(),
-                storage.sun_path.as_mut_ptr().cast(),
-                bytes.len(),
-            );
-        }
-
-        let sun_path_offset = offset_of_path(storage);
-        sun_path_offset
-            + bytes.len()
-            + match bytes.first() {
-                Some(&0) | None => 0,
-                Some(_) => 1,
-            }
-    };
-    Ok(unsafe { SockAddr::new(storage, len as socklen_t) })
-}
-
-// Used in `MsgHdr`.
-#[cfg(not(target_os = "redox"))]
-pub(crate) use libc::msghdr;
-
-#[cfg(not(target_os = "redox"))]
-pub(crate) fn set_msghdr_name(msg: &mut msghdr, name: &SockAddr) {
-    msg.msg_name = name.as_ptr() as *mut _;
-    msg.msg_namelen = name.len();
-}
-
-#[cfg(not(target_os = "redox"))]
-#[allow(clippy::unnecessary_cast)] // IovLen type can be `usize`.
-pub(crate) fn set_msghdr_iov(msg: &mut msghdr, ptr: *mut libc::iovec, len: usize) {
-    msg.msg_iov = ptr;
-    msg.msg_iovlen = min(len, IovLen::MAX as usize) as IovLen;
-}
-
-#[cfg(not(target_os = "redox"))]
-pub(crate) fn set_msghdr_control(msg: &mut msghdr, ptr: *mut libc::c_void, len: usize) {
-    msg.msg_control = ptr;
-    msg.msg_controllen = len as _;
-}
-
-#[cfg(not(target_os = "redox"))]
-pub(crate) fn set_msghdr_flags(msg: &mut msghdr, flags: libc::c_int) {
-    msg.msg_flags = flags;
-}
-
-#[cfg(not(target_os = "redox"))]
-pub(crate) fn msghdr_flags(msg: &msghdr) -> RecvFlags {
-    RecvFlags(msg.msg_flags)
-}
-
-#[cfg(not(target_os = "redox"))]
-pub(crate) fn msghdr_control_len(msg: &msghdr) -> usize {
-    msg.msg_controllen as _
-}
-
-/// Unix only API.
-impl SockAddr {
-    /// Constructs a `SockAddr` with the family `AF_VSOCK` and the provided CID/port.
-    ///
-    /// # Errors
-    ///
-    /// This function can never fail. In a future version of this library it will be made
-    /// infallible.
-    #[allow(unsafe_op_in_unsafe_fn)]
-    #[cfg(all(feature = "all", any(target_os = "android", target_os = "linux")))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(feature = "all", any(target_os = "android", target_os = "linux"))))
-    )]
-    pub fn vsock(cid: u32, port: u32) -> SockAddr {
-        // SAFETY: a `sockaddr_storage` of all zeros is valid.
-        let mut storage = unsafe { mem::zeroed::<sockaddr_storage>() };
-        {
-            let storage: &mut libc::sockaddr_vm =
-                unsafe { &mut *((&mut storage as *mut sockaddr_storage).cast()) };
-            storage.svm_family = libc::AF_VSOCK as sa_family_t;
-            storage.svm_cid = cid;
-            storage.svm_port = port;
-        }
-        unsafe { SockAddr::new(storage, mem::size_of::<libc::sockaddr_vm>() as socklen_t) }
-    }
-
-    /// Returns this address VSOCK CID/port if it is in the `AF_VSOCK` family,
-    /// otherwise return `None`.
-    #[cfg(all(feature = "all", any(target_os = "android", target_os = "linux")))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(feature = "all", any(target_os = "android", target_os = "linux"))))
-    )]
-    pub fn as_vsock_address(&self) -> Option<(u32, u32)> {
-        if self.family() == libc::AF_VSOCK as sa_family_t {
-            // Safety: if the ss_family field is AF_VSOCK then storage must be a sockaddr_vm.
-            let addr = unsafe { &*(self.as_ptr() as *const libc::sockaddr_vm) };
-            Some((addr.svm_cid, addr.svm_port))
-        } else {
-            None
-        }
-    }
-
-    /// Returns true if this address is an unnamed address from the `AF_UNIX` family (for local
-    /// interprocess communication), false otherwise.
-    pub fn is_unnamed(&self) -> bool {
-        self.as_sockaddr_un()
-            .map(|storage| {
-                self.len() == offset_of_path(storage) as _
-                    // On some non-linux platforms a zeroed path is returned for unnamed.
-                    // Abstract addresses only exist on Linux.
-                    // NOTE: although Fuchsia does define `AF_UNIX` it's not actually implemented.
-                    // See https://github.com/rust-lang/socket2/pull/403#discussion_r1123557978
-                    || (cfg!(not(any(target_os = "linux", target_os = "android", target_os = "cygwin")))
-                    && storage.sun_path[0] == 0)
-            })
-            .unwrap_or_default()
-    }
-
-    /// Returns the underlying `sockaddr_un` object if this addres is from the `AF_UNIX` family,
-    /// otherwise returns `None`.
-    pub(crate) fn as_sockaddr_un(&self) -> Option<&libc::sockaddr_un> {
-        self.is_unix().then(|| {
-            // SAFETY: if unix socket, i.e. the `ss_family` field is `AF_UNIX` then storage must be
-            // a `sockaddr_un`.
-            unsafe { &*self.as_ptr().cast::<libc::sockaddr_un>() }
-        })
-    }
-
-    /// Get the length of the path bytes of the address, not including the terminating or initial
-    /// (for abstract names) null byte.
-    ///
-    /// Should not be called on unnamed addresses.
-    fn path_len(&self, storage: &libc::sockaddr_un) -> usize {
-        debug_assert!(!self.is_unnamed());
-        self.len() as usize - offset_of_path(storage) - 1
-    }
-
-    /// Get a u8 slice for the bytes of the pathname or abstract name.
-    ///
-    /// Should not be called on unnamed addresses.
-    fn path_bytes(&self, storage: &libc::sockaddr_un, abstract_name: bool) -> &[u8] {
-        debug_assert!(!self.is_unnamed());
-        // SAFETY: the pointed objects of type `i8` have the same memory layout as `u8`. The path is
-        // the last field in the storage and so its length is equal to
-        //          TOTAL_LENGTH - OFFSET_OF_PATH -1
-        // Where the 1 is either a terminating null if we have a pathname address, or the initial
-        // null byte, if it's an abstract name address. In the latter case, the path bytes start
-        // after the initial null byte, hence the `offset`.
-        // There is no safe way to convert a `&[i8]` to `&[u8]`
-        unsafe {
-            slice::from_raw_parts(
-                (storage.sun_path.as_ptr() as *const u8).offset(abstract_name as isize),
-                self.path_len(storage),
-            )
-        }
-    }
-
-    /// Returns this address as Unix `SocketAddr` if it is an `AF_UNIX` pathname
-    /// address, otherwise returns `None`.
-    pub fn as_unix(&self) -> Option<std::os::unix::net::SocketAddr> {
-        let path = self.as_pathname()?;
-        // SAFETY: we can represent this as a valid pathname, then so can the
-        // standard library.
-        Some(std::os::unix::net::SocketAddr::from_pathname(path).unwrap())
-    }
-
-    /// Returns this address as a `Path` reference if it is an `AF_UNIX`
-    /// pathname address, otherwise returns `None`.
-    pub fn as_pathname(&self) -> Option<&Path> {
-        self.as_sockaddr_un().and_then(|storage| {
-            (self.len() > offset_of_path(storage) as _ && storage.sun_path[0] != 0).then(|| {
-                let path_slice = self.path_bytes(storage, false);
-                Path::new::<OsStr>(OsStrExt::from_bytes(path_slice))
-            })
-        })
-    }
-
-    /// Returns this address as a slice of bytes representing an abstract address if it is an
-    /// `AF_UNIX` abstract address, otherwise returns `None`.
-    ///
-    /// Abstract addresses are a Linux extension, so this method returns `None` on all non-Linux
-    /// platforms.
-    pub fn as_abstract_namespace(&self) -> Option<&[u8]> {
-        // NOTE: although Fuchsia does define `AF_UNIX` it's not actually implemented.
-        // See https://github.com/rust-lang/socket2/pull/403#discussion_r1123557978
-        #[cfg(any(target_os = "linux", target_os = "android", target_os = "cygwin"))]
-        {
-            self.as_sockaddr_un().and_then(|storage| {
-                (self.len() > offset_of_path(storage) as _ && storage.sun_path[0] == 0)
-                    .then(|| self.path_bytes(storage, true))
-            })
-        }
-        #[cfg(not(any(target_os = "linux", target_os = "android", target_os = "cygwin")))]
-        None
-    }
-}
-
-pub(crate) type Socket = c_int;
-
-pub(crate) unsafe fn socket_from_raw(socket: Socket) -> crate::socket::Inner {
-    crate::socket::Inner::from_raw_fd(socket)
-}
-
-pub(crate) fn socket_as_raw(socket: &crate::socket::Inner) -> Socket {
-    socket.as_raw_fd()
-}
-
-pub(crate) fn socket_into_raw(socket: crate::socket::Inner) -> Socket {
-    socket.into_raw_fd()
-}
-
-pub(crate) fn socket(family: c_int, ty: c_int, protocol: c_int) -> io::Result<Socket> {
-    syscall!(socket(family, ty, protocol))
-}
-
-#[cfg(all(feature = "all", unix))]
-#[cfg_attr(docsrs, doc(cfg(all(feature = "all", unix))))]
-pub(crate) fn socketpair(family: c_int, ty: c_int, protocol: c_int) -> io::Result<[Socket; 2]> {
-    let mut fds = [0, 0];
-    syscall!(socketpair(family, ty, protocol, fds.as_mut_ptr())).map(|_| fds)
-}
-
-pub(crate) fn bind(fd: Socket, addr: &SockAddr) -> io::Result<()> {
-    syscall!(bind(fd, addr.as_ptr(), addr.len() as _)).map(|_| ())
-}
-
-pub(crate) fn connect(fd: Socket, addr: &SockAddr) -> io::Result<()> {
-    syscall!(connect(fd, addr.as_ptr(), addr.len())).map(|_| ())
-}
-
-pub(crate) fn poll_connect(socket: &crate::Socket, timeout: Duration) -> io::Result<()> {
-    let start = Instant::now();
-
-    let mut pollfd = libc::pollfd {
-        fd: socket.as_raw(),
-        events: libc::POLLIN | libc::POLLOUT,
-        revents: 0,
-    };
-
-    loop {
-        let elapsed = start.elapsed();
-        if elapsed >= timeout {
-            return Err(io::ErrorKind::TimedOut.into());
-        }
-
-        let timeout = (timeout - elapsed).as_millis();
-        let timeout = timeout.clamp(1, c_int::MAX as u128) as c_int;
-
-        match syscall!(poll(&mut pollfd, 1, timeout)) {
-            Ok(0) => return Err(io::ErrorKind::TimedOut.into()),
-            Ok(_) => {
-                // Error or hang up indicates an error (or failure to connect).
-                if (pollfd.revents & libc::POLLHUP) != 0 || (pollfd.revents & libc::POLLERR) != 0 {
-                    match socket.take_error() {
-                        Ok(Some(err)) | Err(err) => return Err(err),
-                        Ok(None) => {
-                            return Err(io::Error::new(
-                                io::ErrorKind::Other,
-                                "no error set after POLLHUP",
-                            ))
-                        }
-                    }
-                }
-                return Ok(());
-            }
-            // Got interrupted, try again.
-            Err(ref err) if err.kind() == io::ErrorKind::Interrupted => continue,
-            Err(err) => return Err(err),
-        }
-    }
-}
-
-pub(crate) fn listen(fd: Socket, backlog: c_int) -> io::Result<()> {
-    syscall!(listen(fd, backlog)).map(|_| ())
-}
-
-pub(crate) fn accept(fd: Socket) -> io::Result<(Socket, SockAddr)> {
-    // Safety: `accept` initialises the `SockAddr` for us.
-    unsafe { SockAddr::try_init(|storage, len| syscall!(accept(fd, storage.cast(), len))) }
-}
-
-pub(crate) fn getsockname(fd: Socket) -> io::Result<SockAddr> {
-    // Safety: `accept` initialises the `SockAddr` for us.
-    unsafe { SockAddr::try_init(|storage, len| syscall!(getsockname(fd, storage.cast(), len))) }
-        .map(|(_, addr)| addr)
-}
-
-pub(crate) fn getpeername(fd: Socket) -> io::Result<SockAddr> {
-    // Safety: `accept` initialises the `SockAddr` for us.
-    unsafe { SockAddr::try_init(|storage, len| syscall!(getpeername(fd, storage.cast(), len))) }
-        .map(|(_, addr)| addr)
-}
-
-pub(crate) fn try_clone(fd: Socket) -> io::Result<Socket> {
-    syscall!(fcntl(fd, libc::F_DUPFD_CLOEXEC, 0))
-}
-
-#[cfg(all(feature = "all", unix, not(target_os = "vita")))]
-pub(crate) fn nonblocking(fd: Socket) -> io::Result<bool> {
-    let file_status_flags = fcntl_get(fd, libc::F_GETFL)?;
-    Ok((file_status_flags & libc::O_NONBLOCK) != 0)
-}
-
-#[cfg(all(feature = "all", target_os = "vita"))]
-pub(crate) fn nonblocking(fd: Socket) -> io::Result<bool> {
-    unsafe {
-        getsockopt::<Bool>(fd, libc::SOL_SOCKET, libc::SO_NONBLOCK).map(|non_block| non_block != 0)
-    }
-}
-
-#[cfg(not(target_os = "vita"))]
-pub(crate) fn set_nonblocking(fd: Socket, nonblocking: bool) -> io::Result<()> {
-    if nonblocking {
-        fcntl_add(fd, libc::F_GETFL, libc::F_SETFL, libc::O_NONBLOCK)
-    } else {
-        fcntl_remove(fd, libc::F_GETFL, libc::F_SETFL, libc::O_NONBLOCK)
-    }
-}
-
-#[cfg(target_os = "vita")]
-pub(crate) fn set_nonblocking(fd: Socket, nonblocking: bool) -> io::Result<()> {
-    unsafe {
-        setsockopt(
-            fd,
-            libc::SOL_SOCKET,
-            libc::SO_NONBLOCK,
-            nonblocking as libc::c_int,
-        )
-    }
-}
-
-pub(crate) fn shutdown(fd: Socket, how: Shutdown) -> io::Result<()> {
-    let how = match how {
-        Shutdown::Write => libc::SHUT_WR,
-        Shutdown::Read => libc::SHUT_RD,
-        Shutdown::Both => libc::SHUT_RDWR,
-    };
-    syscall!(shutdown(fd, how)).map(|_| ())
-}
-
-pub(crate) fn recv(fd: Socket, buf: &mut [MaybeUninit<u8>], flags: c_int) -> io::Result<usize> {
-    syscall!(recv(
-        fd,
-        buf.as_mut_ptr().cast(),
-        min(buf.len(), MAX_BUF_LEN),
-        flags,
-    ))
-    .map(|n| n as usize)
-}
-
-pub(crate) fn recv_from(
-    fd: Socket,
-    buf: &mut [MaybeUninit<u8>],
-    flags: c_int,
-) -> io::Result<(usize, SockAddr)> {
-    // Safety: `recvfrom` initialises the `SockAddr` for us.
-    unsafe {
-        SockAddr::try_init(|addr, addrlen| {
-            syscall!(recvfrom(
-                fd,
-                buf.as_mut_ptr().cast(),
-                min(buf.len(), MAX_BUF_LEN),
-                flags,
-                addr.cast(),
-                addrlen
-            ))
-            .map(|n| n as usize)
-        })
-    }
-}
-
-pub(crate) fn peek_sender(fd: Socket) -> io::Result<SockAddr> {
-    // Unix-like platforms simply truncate the returned data, so this implementation is trivial.
-    // However, for Windows this requires suppressing the `WSAEMSGSIZE` error,
-    // so that requires a different approach.
-    // NOTE: macOS does not populate `sockaddr` if you pass a zero-sized buffer.
-    let (_, sender) = recv_from(fd, &mut [MaybeUninit::uninit(); 8], MSG_PEEK)?;
-    Ok(sender)
-}
-
-#[cfg(not(target_os = "redox"))]
-pub(crate) fn recv_vectored(
-    fd: Socket,
-    bufs: &mut [crate::MaybeUninitSlice<'_>],
-    flags: c_int,
-) -> io::Result<(usize, RecvFlags)> {
-    let mut msg = MsgHdrMut::new().with_buffers(bufs);
-    let n = recvmsg(fd, &mut msg, flags)?;
-    Ok((n, msg.flags()))
-}
-
-#[cfg(not(target_os = "redox"))]
-pub(crate) fn recv_from_vectored(
-    fd: Socket,
-    bufs: &mut [crate::MaybeUninitSlice<'_>],
-    flags: c_int,
-) -> io::Result<(usize, RecvFlags, SockAddr)> {
-    let mut msg = MsgHdrMut::new().with_buffers(bufs);
-    // SAFETY: `recvmsg` initialises the address storage and we set the length
-    // manually.
-    let (n, addr) = unsafe {
-        SockAddr::try_init(|storage, len| {
-            msg.inner.msg_name = storage.cast();
-            msg.inner.msg_namelen = *len;
-            let n = recvmsg(fd, &mut msg, flags)?;
-            // Set the correct address length.
-            *len = msg.inner.msg_namelen;
-            Ok(n)
-        })?
-    };
-    Ok((n, msg.flags(), addr))
-}
-
-#[cfg(not(target_os = "redox"))]
-pub(crate) fn recvmsg(
-    fd: Socket,
-    msg: &mut MsgHdrMut<'_, '_, '_>,
-    flags: c_int,
-) -> io::Result<usize> {
-    syscall!(recvmsg(fd, &mut msg.inner, flags)).map(|n| n as usize)
-}
-
-pub(crate) fn send(fd: Socket, buf: &[u8], flags: c_int) -> io::Result<usize> {
-    syscall!(send(
-        fd,
-        buf.as_ptr().cast(),
-        min(buf.len(), MAX_BUF_LEN),
-        flags,
-    ))
-    .map(|n| n as usize)
-}
-
-#[cfg(not(target_os = "redox"))]
-pub(crate) fn send_vectored(fd: Socket, bufs: &[IoSlice<'_>], flags: c_int) -> io::Result<usize> {
-    let msg = MsgHdr::new().with_buffers(bufs);
-    sendmsg(fd, &msg, flags)
-}
-
-pub(crate) fn send_to(fd: Socket, buf: &[u8], addr: &SockAddr, flags: c_int) -> io::Result<usize> {
-    syscall!(sendto(
-        fd,
-        buf.as_ptr().cast(),
-        min(buf.len(), MAX_BUF_LEN),
-        flags,
-        addr.as_ptr(),
-        addr.len(),
-    ))
-    .map(|n| n as usize)
-}
-
-#[cfg(not(target_os = "redox"))]
-pub(crate) fn send_to_vectored(
-    fd: Socket,
-    bufs: &[IoSlice<'_>],
-    addr: &SockAddr,
-    flags: c_int,
-) -> io::Result<usize> {
-    let msg = MsgHdr::new().with_addr(addr).with_buffers(bufs);
-    sendmsg(fd, &msg, flags)
-}
-
-#[cfg(not(target_os = "redox"))]
-pub(crate) fn sendmsg(fd: Socket, msg: &MsgHdr<'_, '_, '_>, flags: c_int) -> io::Result<usize> {
-    syscall!(sendmsg(fd, &msg.inner, flags)).map(|n| n as usize)
-}
-
-/// Wrapper around `getsockopt` to deal with platform specific timeouts.
-pub(crate) fn timeout_opt(fd: Socket, opt: c_int, val: c_int) -> io::Result<Option<Duration>> {
-    unsafe { getsockopt(fd, opt, val).map(from_timeval) }
-}
-
-const fn from_timeval(duration: libc::timeval) -> Option<Duration> {
-    if duration.tv_sec == 0 && duration.tv_usec == 0 {
-        None
-    } else {
-        let sec = duration.tv_sec as u64;
-        let nsec = (duration.tv_usec as u32) * 1000;
-        Some(Duration::new(sec, nsec))
-    }
-}
-
-/// Wrapper around `setsockopt` to deal with platform specific timeouts.
-pub(crate) fn set_timeout_opt(
-    fd: Socket,
-    opt: c_int,
-    val: c_int,
-    duration: Option<Duration>,
-) -> io::Result<()> {
-    let duration = into_timeval(duration);
-    unsafe { setsockopt(fd, opt, val, duration) }
-}
-
-fn into_timeval(duration: Option<Duration>) -> libc::timeval {
-    match duration {
-        // https://github.com/rust-lang/libc/issues/1848
-        #[cfg_attr(target_env = "musl", allow(deprecated))]
-        Some(duration) => libc::timeval {
-            tv_sec: min(duration.as_secs(), libc::time_t::MAX as u64) as libc::time_t,
-            tv_usec: duration.subsec_micros() as libc::suseconds_t,
-        },
-        None => libc::timeval {
-            tv_sec: 0,
-            tv_usec: 0,
-        },
-    }
-}
-
-#[cfg(all(
-    feature = "all",
-    not(any(target_os = "haiku", target_os = "openbsd", target_os = "vita"))
-))]
-#[cfg_attr(
-    docsrs,
-    doc(cfg(all(
-        feature = "all",
-        not(any(target_os = "haiku", target_os = "openbsd", target_os = "vita"))
-    )))
-)]
-pub(crate) fn keepalive_time(fd: Socket) -> io::Result<Duration> {
-    unsafe {
-        getsockopt::<c_int>(fd, IPPROTO_TCP, KEEPALIVE_TIME)
-            .map(|secs| Duration::from_secs(secs as u64))
-    }
-}
-
-#[allow(unused_variables)]
-pub(crate) fn set_tcp_keepalive(fd: Socket, keepalive: &TcpKeepalive) -> io::Result<()> {
-    #[cfg(not(any(
-        target_os = "haiku",
-        target_os = "openbsd",
-        target_os = "nto",
-        target_os = "vita"
-    )))]
-    if let Some(time) = keepalive.time {
-        let secs = into_secs(time);
-        unsafe { setsockopt(fd, libc::IPPROTO_TCP, KEEPALIVE_TIME, secs)? }
-    }
-
-    #[cfg(any(
-        target_os = "aix",
-        target_os = "android",
-        target_os = "dragonfly",
-        target_os = "freebsd",
-        target_os = "fuchsia",
-        target_os = "hurd",
-        target_os = "illumos",
-        target_os = "ios",
-        target_os = "visionos",
-        target_os = "linux",
-        target_os = "macos",
-        target_os = "netbsd",
-        target_os = "tvos",
-        target_os = "watchos",
-        target_os = "cygwin",
-    ))]
-    {
-        if let Some(interval) = keepalive.interval {
-            let secs = into_secs(interval);
-            unsafe { setsockopt(fd, libc::IPPROTO_TCP, libc::TCP_KEEPINTVL, secs)? }
-        }
-
-        if let Some(retries) = keepalive.retries {
-            unsafe { setsockopt(fd, libc::IPPROTO_TCP, libc::TCP_KEEPCNT, retries as c_int)? }
-        }
-    }
-
-    #[cfg(target_os = "nto")]
-    if let Some(time) = keepalive.time {
-        let secs = into_timeval(Some(time));
-        unsafe { setsockopt(fd, libc::IPPROTO_TCP, KEEPALIVE_TIME, secs)? }
-    }
-
-    Ok(())
-}
-
-#[cfg(not(any(
-    target_os = "haiku",
-    target_os = "openbsd",
-    target_os = "nto",
-    target_os = "vita"
-)))]
-fn into_secs(duration: Duration) -> c_int {
-    min(duration.as_secs(), c_int::MAX as u64) as c_int
-}
-
-/// Get the flags using `cmd`.
-#[cfg(not(target_os = "vita"))]
-fn fcntl_get(fd: Socket, cmd: c_int) -> io::Result<c_int> {
-    syscall!(fcntl(fd, cmd))
-}
-
-/// Add `flag` to the current set flags of `F_GETFD`.
-#[cfg(not(target_os = "vita"))]
-fn fcntl_add(fd: Socket, get_cmd: c_int, set_cmd: c_int, flag: c_int) -> io::Result<()> {
-    let previous = fcntl_get(fd, get_cmd)?;
-    let new = previous | flag;
-    if new != previous {
-        syscall!(fcntl(fd, set_cmd, new)).map(|_| ())
-    } else {
-        // Flag was already set.
-        Ok(())
-    }
-}
-
-/// Remove `flag` to the current set flags of `F_GETFD`.
-#[cfg(not(target_os = "vita"))]
-fn fcntl_remove(fd: Socket, get_cmd: c_int, set_cmd: c_int, flag: c_int) -> io::Result<()> {
-    let previous = fcntl_get(fd, get_cmd)?;
-    let new = previous & !flag;
-    if new != previous {
-        syscall!(fcntl(fd, set_cmd, new)).map(|_| ())
-    } else {
-        // Flag was already set.
-        Ok(())
-    }
-}
-
-/// Caller must ensure `T` is the correct type for `opt` and `val`.
-pub(crate) unsafe fn getsockopt<T>(fd: Socket, opt: c_int, val: c_int) -> io::Result<T> {
-    let mut payload: MaybeUninit<T> = MaybeUninit::uninit();
-    let mut len = size_of::<T>() as libc::socklen_t;
-    syscall!(getsockopt(
-        fd,
-        opt,
-        val,
-        payload.as_mut_ptr().cast(),
-        &mut len,
-    ))
-    .map(|_| {
-        debug_assert_eq!(len as usize, size_of::<T>());
-        // Safety: `getsockopt` initialised `payload` for us.
-        payload.assume_init()
-    })
-}
-
-/// Caller must ensure `T` is the correct type for `opt` and `val`.
-pub(crate) unsafe fn setsockopt<T>(
-    fd: Socket,
-    opt: c_int,
-    val: c_int,
-    payload: T,
-) -> io::Result<()> {
-    let payload = ptr::addr_of!(payload).cast();
-    syscall!(setsockopt(
-        fd,
-        opt,
-        val,
-        payload,
-        mem::size_of::<T>() as libc::socklen_t,
-    ))
-    .map(|_| ())
-}
-
-pub(crate) const fn to_in_addr(addr: &Ipv4Addr) -> in_addr {
-    // `s_addr` is stored as BE on all machines, and the array is in BE order.
-    // So the native endian conversion method is used so that it's never
-    // swapped.
-    in_addr {
-        s_addr: u32::from_ne_bytes(addr.octets()),
-    }
-}
-
-pub(crate) fn from_in_addr(in_addr: in_addr) -> Ipv4Addr {
-    Ipv4Addr::from(in_addr.s_addr.to_ne_bytes())
-}
-
-pub(crate) const fn to_in6_addr(addr: &Ipv6Addr) -> in6_addr {
-    in6_addr {
-        s6_addr: addr.octets(),
-    }
-}
-
-pub(crate) fn from_in6_addr(addr: in6_addr) -> Ipv6Addr {
-    Ipv6Addr::from(addr.s6_addr)
-}
-
-#[cfg(not(any(
-    target_os = "aix",
-    target_os = "haiku",
-    target_os = "illumos",
-    target_os = "netbsd",
-    target_os = "openbsd",
-    target_os = "redox",
-    target_os = "solaris",
-    target_os = "nto",
-    target_os = "espidf",
-    target_os = "vita",
-    target_os = "cygwin",
-)))]
-pub(crate) const fn to_mreqn(
-    multiaddr: &Ipv4Addr,
-    interface: &crate::socket::InterfaceIndexOrAddress,
-) -> libc::ip_mreqn {
-    match interface {
-        crate::socket::InterfaceIndexOrAddress::Index(interface) => libc::ip_mreqn {
-            imr_multiaddr: to_in_addr(multiaddr),
-            imr_address: to_in_addr(&Ipv4Addr::UNSPECIFIED),
-            imr_ifindex: *interface as _,
-        },
-        crate::socket::InterfaceIndexOrAddress::Address(interface) => libc::ip_mreqn {
-            imr_multiaddr: to_in_addr(multiaddr),
-            imr_address: to_in_addr(interface),
-            imr_ifindex: 0,
-        },
-    }
-}
-
-#[cfg(all(
-    feature = "all",
-    any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-))]
-pub(crate) fn original_dst(fd: Socket) -> io::Result<SockAddr> {
-    // Safety: `getsockopt` initialises the `SockAddr` for us.
-    unsafe {
-        SockAddr::try_init(|storage, len| {
-            syscall!(getsockopt(
-                fd,
-                libc::SOL_IP,
-                libc::SO_ORIGINAL_DST,
-                storage.cast(),
-                len
-            ))
-        })
-    }
-    .map(|(_, addr)| addr)
-}
-
-/// Get the value for the `IP6T_SO_ORIGINAL_DST` option on this socket.
-///
-/// This value contains the original destination IPv6 address of the connection
-/// redirected using `ip6tables` `REDIRECT` or `TPROXY`.
-#[cfg(all(feature = "all", any(target_os = "android", target_os = "linux")))]
-pub(crate) fn original_dst_ipv6(fd: Socket) -> io::Result<SockAddr> {
-    // Safety: `getsockopt` initialises the `SockAddr` for us.
-    unsafe {
-        SockAddr::try_init(|storage, len| {
-            syscall!(getsockopt(
-                fd,
-                libc::SOL_IPV6,
-                libc::IP6T_SO_ORIGINAL_DST,
-                storage.cast(),
-                len
-            ))
-        })
-    }
-    .map(|(_, addr)| addr)
-}
-
-/// Unix only API.
-impl crate::Socket {
-    /// Accept a new incoming connection from this listener.
-    ///
-    /// This function directly corresponds to the `accept4(2)` function.
-    ///
-    /// This function will block the calling thread until a new connection is
-    /// established. When established, the corresponding `Socket` and the remote
-    /// peer's address will be returned.
-    #[doc = man_links!(unix: accept4(2))]
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "android",
-            target_os = "dragonfly",
-            target_os = "freebsd",
-            target_os = "fuchsia",
-            target_os = "illumos",
-            target_os = "linux",
-            target_os = "netbsd",
-            target_os = "openbsd",
-            target_os = "cygwin",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "android",
-                target_os = "dragonfly",
-                target_os = "freebsd",
-                target_os = "fuchsia",
-                target_os = "illumos",
-                target_os = "linux",
-                target_os = "netbsd",
-                target_os = "openbsd",
-            )
-        )))
-    )]
-    pub fn accept4(&self, flags: c_int) -> io::Result<(crate::Socket, SockAddr)> {
-        self._accept4(flags)
-    }
-
-    #[cfg(any(
-        target_os = "android",
-        target_os = "dragonfly",
-        target_os = "freebsd",
-        target_os = "fuchsia",
-        target_os = "illumos",
-        target_os = "linux",
-        target_os = "netbsd",
-        target_os = "openbsd",
-        target_os = "cygwin",
-    ))]
-    pub(crate) fn _accept4(&self, flags: c_int) -> io::Result<(crate::Socket, SockAddr)> {
-        // Safety: `accept4` initialises the `SockAddr` for us.
-        unsafe {
-            SockAddr::try_init(|storage, len| {
-                syscall!(accept4(self.as_raw(), storage.cast(), len, flags))
-                    .map(crate::Socket::from_raw)
-            })
-        }
-    }
-
-    /// Sets `CLOEXEC` on the socket.
-    ///
-    /// # Notes
-    ///
-    /// On supported platforms you can use [`Type::cloexec`].
-    #[cfg_attr(
-        any(
-            target_os = "ios",
-            target_os = "visionos",
-            target_os = "macos",
-            target_os = "tvos",
-            target_os = "watchos"
-        ),
-        allow(rustdoc::broken_intra_doc_links)
-    )]
-    #[cfg(all(feature = "all", not(target_os = "vita")))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", unix))))]
-    pub fn set_cloexec(&self, close_on_exec: bool) -> io::Result<()> {
-        self._set_cloexec(close_on_exec)
-    }
-
-    #[cfg(not(target_os = "vita"))]
-    pub(crate) fn _set_cloexec(&self, close_on_exec: bool) -> io::Result<()> {
-        if close_on_exec {
-            fcntl_add(
-                self.as_raw(),
-                libc::F_GETFD,
-                libc::F_SETFD,
-                libc::FD_CLOEXEC,
-            )
-        } else {
-            fcntl_remove(
-                self.as_raw(),
-                libc::F_GETFD,
-                libc::F_SETFD,
-                libc::FD_CLOEXEC,
-            )
-        }
-    }
-
-    /// Sets `SO_PEERCRED` to null on the socket.
-    ///
-    /// This is a Cygwin extension.
-    ///
-    /// Normally the Unix domain sockets of Cygwin are implemented by TCP sockets,
-    /// so it performs a handshake on `connect` and `accept` to verify the remote
-    /// connection and exchange peer cred info. At the time of writing, this
-    /// means that `connect` on a Unix domain socket will block until the server
-    /// calls `accept` on Cygwin. This behavior is inconsistent with most other
-    /// platforms, and this option can be used to disable that.
-    ///
-    /// See also: the [mailing list](https://inbox.sourceware.org/cygwin/TYCPR01MB10926FF8926CA63704867ADC8F8AA2@TYCPR01MB10926.jpnprd01.prod.outlook.com/)
-    #[cfg(target_os = "cygwin")]
-    #[cfg(any(doc, target_os = "cygwin"))]
-    pub fn set_no_peercred(&self) -> io::Result<()> {
-        syscall!(setsockopt(
-            self.as_raw(),
-            libc::SOL_SOCKET,
-            libc::SO_PEERCRED,
-            ptr::null_mut(),
-            0,
-        ))
-        .map(|_| ())
-    }
-
-    /// Sets `SO_NOSIGPIPE` on the socket.
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "ios",
-            target_os = "visionos",
-            target_os = "macos",
-            target_os = "tvos",
-            target_os = "watchos",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "ios",
-                target_os = "visionos",
-                target_os = "macos",
-                target_os = "tvos",
-                target_os = "watchos",
-            )
-        )))
-    )]
-    pub fn set_nosigpipe(&self, nosigpipe: bool) -> io::Result<()> {
-        self._set_nosigpipe(nosigpipe)
-    }
-
-    #[cfg(any(
-        target_os = "ios",
-        target_os = "visionos",
-        target_os = "macos",
-        target_os = "tvos",
-        target_os = "watchos",
-    ))]
-    pub(crate) fn _set_nosigpipe(&self, nosigpipe: bool) -> io::Result<()> {
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                libc::SOL_SOCKET,
-                libc::SO_NOSIGPIPE,
-                nosigpipe as c_int,
-            )
-        }
-    }
-
-    /// Gets the value of the `TCP_MAXSEG` option on this socket.
-    ///
-    /// For more information about this option, see [`set_mss`].
-    ///
-    /// [`set_mss`]: crate::Socket::set_mss
-    #[cfg(all(feature = "all", not(target_os = "redox")))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", unix, not(target_os = "redox")))))]
-    pub fn mss(&self) -> io::Result<u32> {
-        unsafe {
-            getsockopt::<c_int>(self.as_raw(), libc::IPPROTO_TCP, libc::TCP_MAXSEG)
-                .map(|mss| mss as u32)
-        }
-    }
-
-    /// Sets the value of the `TCP_MAXSEG` option on this socket.
-    ///
-    /// The `TCP_MAXSEG` option denotes the TCP Maximum Segment Size and is only
-    /// available on TCP sockets.
-    #[cfg(all(feature = "all", not(target_os = "redox")))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", unix, not(target_os = "redox")))))]
-    pub fn set_mss(&self, mss: u32) -> io::Result<()> {
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                libc::IPPROTO_TCP,
-                libc::TCP_MAXSEG,
-                mss as c_int,
-            )
-        }
-    }
-
-    /// Returns `true` if `listen(2)` was called on this socket by checking the
-    /// `SO_ACCEPTCONN` option on this socket.
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "aix",
-            target_os = "android",
-            target_os = "freebsd",
-            target_os = "fuchsia",
-            target_os = "linux",
-            target_os = "cygwin",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "aix",
-                target_os = "android",
-                target_os = "freebsd",
-                target_os = "fuchsia",
-                target_os = "linux",
-            )
-        )))
-    )]
-    pub fn is_listener(&self) -> io::Result<bool> {
-        unsafe {
-            getsockopt::<c_int>(self.as_raw(), libc::SOL_SOCKET, libc::SO_ACCEPTCONN)
-                .map(|v| v != 0)
-        }
-    }
-
-    /// Returns the [`Domain`] of this socket by checking the `SO_DOMAIN` option
-    /// on this socket.
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "android",
-            // TODO: add FreeBSD.
-            // target_os = "freebsd",
-            target_os = "fuchsia",
-            target_os = "linux",
-        )
-    ))]
-    #[cfg_attr(docsrs, doc(cfg(all(
-        feature = "all",
-        any(
-            target_os = "android",
-            // TODO: add FreeBSD.
-            // target_os = "freebsd",
-            target_os = "fuchsia",
-            target_os = "linux",
-        )
-    ))))]
-    pub fn domain(&self) -> io::Result<Domain> {
-        unsafe { getsockopt::<c_int>(self.as_raw(), libc::SOL_SOCKET, libc::SO_DOMAIN).map(Domain) }
-    }
-
-    /// Returns the [`Protocol`] of this socket by checking the `SO_PROTOCOL`
-    /// option on this socket.
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "android",
-            target_os = "freebsd",
-            target_os = "fuchsia",
-            target_os = "linux",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "android",
-                target_os = "freebsd",
-                target_os = "fuchsia",
-                target_os = "linux",
-            )
-        )))
-    )]
-    pub fn protocol(&self) -> io::Result<Option<Protocol>> {
-        unsafe {
-            getsockopt::<c_int>(self.as_raw(), libc::SOL_SOCKET, libc::SO_PROTOCOL).map(|v| match v
-            {
-                0 => None,
-                p => Some(Protocol(p)),
-            })
-        }
-    }
-
-    /// Gets the value for the `SO_MARK` option on this socket.
-    ///
-    /// This value gets the socket mark field for each packet sent through
-    /// this socket.
-    ///
-    /// On Linux this function requires the `CAP_NET_ADMIN` capability.
-    #[cfg(all(
-        feature = "all",
-        any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-        )))
-    )]
-    pub fn mark(&self) -> io::Result<u32> {
-        unsafe {
-            getsockopt::<c_int>(self.as_raw(), libc::SOL_SOCKET, libc::SO_MARK)
-                .map(|mark| mark as u32)
-        }
-    }
-
-    /// Sets the value for the `SO_MARK` option on this socket.
-    ///
-    /// This value sets the socket mark field for each packet sent through
-    /// this socket. Changing the mark can be used for mark-based routing
-    /// without netfilter or for packet filtering.
-    ///
-    /// On Linux this function requires the `CAP_NET_ADMIN` capability.
-    #[cfg(all(
-        feature = "all",
-        any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-        )))
-    )]
-    pub fn set_mark(&self, mark: u32) -> io::Result<()> {
-        unsafe {
-            setsockopt::<c_int>(
-                self.as_raw(),
-                libc::SOL_SOCKET,
-                libc::SO_MARK,
-                mark as c_int,
-            )
-        }
-    }
-
-    /// Get the value of the `TCP_CORK` option on this socket.
-    ///
-    /// For more information about this option, see [`set_cork`].
-    ///
-    /// [`set_cork`]: crate::Socket::set_cork
-    #[cfg(all(
-        feature = "all",
-        any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-        )))
-    )]
-    pub fn cork(&self) -> io::Result<bool> {
-        unsafe {
-            getsockopt::<Bool>(self.as_raw(), libc::IPPROTO_TCP, libc::TCP_CORK)
-                .map(|cork| cork != 0)
-        }
-    }
-
-    /// Set the value of the `TCP_CORK` option on this socket.
-    ///
-    /// If set, don't send out partial frames. All queued partial frames are
-    /// sent when the option is cleared again. There is a 200 millisecond ceiling on
-    /// the time for which output is corked by `TCP_CORK`. If this ceiling is reached,
-    /// then queued data is automatically transmitted.
-    #[cfg(all(
-        feature = "all",
-        any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-        )))
-    )]
-    pub fn set_cork(&self, cork: bool) -> io::Result<()> {
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                libc::IPPROTO_TCP,
-                libc::TCP_CORK,
-                cork as c_int,
-            )
-        }
-    }
-
-    /// Get the value of the `TCP_QUICKACK` option on this socket.
-    ///
-    /// For more information about this option, see [`set_quickack`].
-    ///
-    /// [`set_quickack`]: crate::Socket::set_quickack
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "android",
-            target_os = "fuchsia",
-            target_os = "linux",
-            target_os = "cygwin",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "android",
-                target_os = "fuchsia",
-                target_os = "linux",
-                target_os = "cygwin"
-            )
-        )))
-    )]
-    pub fn quickack(&self) -> io::Result<bool> {
-        unsafe {
-            getsockopt::<Bool>(self.as_raw(), libc::IPPROTO_TCP, libc::TCP_QUICKACK)
-                .map(|quickack| quickack != 0)
-        }
-    }
-
-    /// Set the value of the `TCP_QUICKACK` option on this socket.
-    ///
-    /// If set, acks are sent immediately, rather than delayed if needed in accordance to normal
-    /// TCP operation. This flag is not permanent, it only enables a switch to or from quickack mode.
-    /// Subsequent operation of the TCP protocol will once again enter/leave quickack mode depending on
-    /// internal protocol processing and factors such as delayed ack timeouts occurring and data transfer.
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "android",
-            target_os = "fuchsia",
-            target_os = "linux",
-            target_os = "cygwin",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "android",
-                target_os = "fuchsia",
-                target_os = "linux",
-                target_os = "cygwin"
-            )
-        )))
-    )]
-    pub fn set_quickack(&self, quickack: bool) -> io::Result<()> {
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                libc::IPPROTO_TCP,
-                libc::TCP_QUICKACK,
-                quickack as c_int,
-            )
-        }
-    }
-
-    /// Get the value of the `TCP_THIN_LINEAR_TIMEOUTS` option on this socket.
-    ///
-    /// For more information about this option, see [`set_thin_linear_timeouts`].
-    ///
-    /// [`set_thin_linear_timeouts`]: crate::Socket::set_thin_linear_timeouts
-    #[cfg(all(
-        feature = "all",
-        any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-        )))
-    )]
-    pub fn thin_linear_timeouts(&self) -> io::Result<bool> {
-        unsafe {
-            getsockopt::<Bool>(
-                self.as_raw(),
-                libc::IPPROTO_TCP,
-                libc::TCP_THIN_LINEAR_TIMEOUTS,
-            )
-            .map(|timeouts| timeouts != 0)
-        }
-    }
-
-    /// Set the value of the `TCP_THIN_LINEAR_TIMEOUTS` option on this socket.
-    ///
-    /// If set, the kernel will dynamically detect a thin-stream connection if there are less than four packets in flight.
-    /// With less than four packets in flight the normal TCP fast retransmission will not be effective.
-    /// The kernel will modify the retransmission to avoid the very high latencies that thin stream suffer because of exponential backoff.
-    #[cfg(all(
-        feature = "all",
-        any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-        )))
-    )]
-    pub fn set_thin_linear_timeouts(&self, timeouts: bool) -> io::Result<()> {
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                libc::IPPROTO_TCP,
-                libc::TCP_THIN_LINEAR_TIMEOUTS,
-                timeouts as c_int,
-            )
-        }
-    }
-
-    /// Gets the value for the `SO_BINDTODEVICE` option on this socket.
-    ///
-    /// This value gets the socket binded device's interface name.
-    #[cfg(all(
-        feature = "all",
-        any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-        )))
-    )]
-    pub fn device(&self) -> io::Result<Option<Vec<u8>>> {
-        // TODO: replace with `MaybeUninit::uninit_array` once stable.
-        let mut buf: [MaybeUninit<u8>; libc::IFNAMSIZ] =
-            unsafe { MaybeUninit::uninit().assume_init() };
-        let mut len = buf.len() as libc::socklen_t;
-        syscall!(getsockopt(
-            self.as_raw(),
-            libc::SOL_SOCKET,
-            libc::SO_BINDTODEVICE,
-            buf.as_mut_ptr().cast(),
-            &mut len,
-        ))?;
-        if len == 0 {
-            Ok(None)
-        } else {
-            let buf = &buf[..len as usize - 1];
-            // TODO: use `MaybeUninit::slice_assume_init_ref` once stable.
-            Ok(Some(unsafe { &*(buf as *const [_] as *const [u8]) }.into()))
-        }
-    }
-
-    /// Sets the value for the `SO_BINDTODEVICE` option on this socket.
-    ///
-    /// If a socket is bound to an interface, only packets received from that
-    /// particular interface are processed by the socket. Note that this only
-    /// works for some socket types, particularly `AF_INET` sockets.
-    ///
-    /// If `interface` is `None` or an empty string it removes the binding.
-    #[cfg(all(
-        feature = "all",
-        any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-        )))
-    )]
-    pub fn bind_device(&self, interface: Option<&[u8]>) -> io::Result<()> {
-        let (value, len) = if let Some(interface) = interface {
-            (interface.as_ptr(), interface.len())
-        } else {
-            (ptr::null(), 0)
-        };
-        syscall!(setsockopt(
-            self.as_raw(),
-            libc::SOL_SOCKET,
-            libc::SO_BINDTODEVICE,
-            value.cast(),
-            len as libc::socklen_t,
-        ))
-        .map(|_| ())
-    }
-
-    /// Sets the value for the `SO_SETFIB` option on this socket.
-    ///
-    /// Bind socket to the specified forwarding table (VRF) on a FreeBSD.
-    #[cfg(all(feature = "all", target_os = "freebsd"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "freebsd"))))]
-    pub fn set_fib(&self, fib: u32) -> io::Result<()> {
-        syscall!(setsockopt(
-            self.as_raw(),
-            libc::SOL_SOCKET,
-            libc::SO_SETFIB,
-            (&fib as *const u32).cast(),
-            mem::size_of::<u32>() as libc::socklen_t,
-        ))
-        .map(|_| ())
-    }
-
-    /// This method is deprecated, use [`crate::Socket::bind_device_by_index_v4`].
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "ios",
-            target_os = "visionos",
-            target_os = "macos",
-            target_os = "tvos",
-            target_os = "watchos",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "ios",
-                target_os = "visionos",
-                target_os = "macos",
-                target_os = "tvos",
-                target_os = "watchos",
-            )
-        )))
-    )]
-    #[deprecated = "Use `Socket::bind_device_by_index_v4` instead"]
-    pub fn bind_device_by_index(&self, interface: Option<NonZeroU32>) -> io::Result<()> {
-        self.bind_device_by_index_v4(interface)
-    }
-
-    /// Sets the value for `IP_BOUND_IF` option on this socket.
-    ///
-    /// If a socket is bound to an interface, only packets received from that
-    /// particular interface are processed by the socket.
-    ///
-    /// If `interface` is `None`, the binding is removed. If the `interface`
-    /// index is not valid, an error is returned.
-    ///
-    /// One can use [`libc::if_nametoindex`] to convert an interface alias to an
-    /// index.
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "ios",
-            target_os = "visionos",
-            target_os = "macos",
-            target_os = "tvos",
-            target_os = "watchos",
-            target_os = "illumos",
-            target_os = "solaris",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "ios",
-                target_os = "visionos",
-                target_os = "macos",
-                target_os = "tvos",
-                target_os = "watchos",
-            )
-        )))
-    )]
-    pub fn bind_device_by_index_v4(&self, interface: Option<NonZeroU32>) -> io::Result<()> {
-        let index = interface.map_or(0, NonZeroU32::get);
-        unsafe { setsockopt(self.as_raw(), IPPROTO_IP, libc::IP_BOUND_IF, index) }
-    }
-
-    /// Sets the value for `IPV6_BOUND_IF` option on this socket.
-    ///
-    /// If a socket is bound to an interface, only packets received from that
-    /// particular interface are processed by the socket.
-    ///
-    /// If `interface` is `None`, the binding is removed. If the `interface`
-    /// index is not valid, an error is returned.
-    ///
-    /// One can use [`libc::if_nametoindex`] to convert an interface alias to an
-    /// index.
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "ios",
-            target_os = "visionos",
-            target_os = "macos",
-            target_os = "tvos",
-            target_os = "watchos",
-            target_os = "illumos",
-            target_os = "solaris",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "ios",
-                target_os = "visionos",
-                target_os = "macos",
-                target_os = "tvos",
-                target_os = "watchos",
-            )
-        )))
-    )]
-    pub fn bind_device_by_index_v6(&self, interface: Option<NonZeroU32>) -> io::Result<()> {
-        let index = interface.map_or(0, NonZeroU32::get);
-        unsafe { setsockopt(self.as_raw(), IPPROTO_IPV6, libc::IPV6_BOUND_IF, index) }
-    }
-
-    /// Gets the value for `IP_BOUND_IF` option on this socket, i.e. the index
-    /// for the interface to which the socket is bound.
-    ///
-    /// Returns `None` if the socket is not bound to any interface, otherwise
-    /// returns an interface index.
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "ios",
-            target_os = "visionos",
-            target_os = "macos",
-            target_os = "tvos",
-            target_os = "watchos",
-            target_os = "illumos",
-            target_os = "solaris",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "ios",
-                target_os = "visionos",
-                target_os = "macos",
-                target_os = "tvos",
-                target_os = "watchos",
-            )
-        )))
-    )]
-    pub fn device_index_v4(&self) -> io::Result<Option<NonZeroU32>> {
-        let index =
-            unsafe { getsockopt::<libc::c_uint>(self.as_raw(), IPPROTO_IP, libc::IP_BOUND_IF)? };
-        Ok(NonZeroU32::new(index))
-    }
-
-    /// This method is deprecated, use [`crate::Socket::device_index_v4`].
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "ios",
-            target_os = "visionos",
-            target_os = "macos",
-            target_os = "tvos",
-            target_os = "watchos",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "ios",
-                target_os = "visionos",
-                target_os = "macos",
-                target_os = "tvos",
-                target_os = "watchos",
-            )
-        )))
-    )]
-    #[deprecated = "Use `Socket::device_index_v4` instead"]
-    pub fn device_index(&self) -> io::Result<Option<NonZeroU32>> {
-        self.device_index_v4()
-    }
-
-    /// Gets the value for `IPV6_BOUND_IF` option on this socket, i.e. the index
-    /// for the interface to which the socket is bound.
-    ///
-    /// Returns `None` if the socket is not bound to any interface, otherwise
-    /// returns an interface index.
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "ios",
-            target_os = "visionos",
-            target_os = "macos",
-            target_os = "tvos",
-            target_os = "watchos",
-            target_os = "illumos",
-            target_os = "solaris",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "ios",
-                target_os = "visionos",
-                target_os = "macos",
-                target_os = "tvos",
-                target_os = "watchos",
-            )
-        )))
-    )]
-    pub fn device_index_v6(&self) -> io::Result<Option<NonZeroU32>> {
-        let index = unsafe {
-            getsockopt::<libc::c_uint>(self.as_raw(), IPPROTO_IPV6, libc::IPV6_BOUND_IF)?
-        };
-        Ok(NonZeroU32::new(index))
-    }
-
-    /// Get the value of the `SO_INCOMING_CPU` option on this socket.
-    ///
-    /// For more information about this option, see [`set_cpu_affinity`].
-    ///
-    /// [`set_cpu_affinity`]: crate::Socket::set_cpu_affinity
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn cpu_affinity(&self) -> io::Result<usize> {
-        unsafe {
-            getsockopt::<c_int>(self.as_raw(), libc::SOL_SOCKET, libc::SO_INCOMING_CPU)
-                .map(|cpu| cpu as usize)
-        }
-    }
-
-    /// Set value for the `SO_INCOMING_CPU` option on this socket.
-    ///
-    /// Sets the CPU affinity of the socket.
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn set_cpu_affinity(&self, cpu: usize) -> io::Result<()> {
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                libc::SOL_SOCKET,
-                libc::SO_INCOMING_CPU,
-                cpu as c_int,
-            )
-        }
-    }
-
-    /// Get the value of the `SO_REUSEPORT` option on this socket.
-    ///
-    /// For more information about this option, see [`set_reuse_port`].
-    ///
-    /// [`set_reuse_port`]: crate::Socket::set_reuse_port
-    #[cfg(all(
-        feature = "all",
-        not(any(target_os = "solaris", target_os = "illumos", target_os = "cygwin"))
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            unix,
-            not(any(target_os = "solaris", target_os = "illumos", target_os = "cygwin"))
-        )))
-    )]
-    pub fn reuse_port(&self) -> io::Result<bool> {
-        unsafe {
-            getsockopt::<c_int>(self.as_raw(), libc::SOL_SOCKET, libc::SO_REUSEPORT)
-                .map(|reuse| reuse != 0)
-        }
-    }
-
-    /// Set value for the `SO_REUSEPORT` option on this socket.
-    ///
-    /// This indicates that further calls to `bind` may allow reuse of local
-    /// addresses. For IPv4 sockets this means that a socket may bind even when
-    /// there's a socket already listening on this port.
-    #[cfg(all(
-        feature = "all",
-        not(any(target_os = "solaris", target_os = "illumos", target_os = "cygwin"))
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            unix,
-            not(any(target_os = "solaris", target_os = "illumos", target_os = "cygwin"))
-        )))
-    )]
-    pub fn set_reuse_port(&self, reuse: bool) -> io::Result<()> {
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                libc::SOL_SOCKET,
-                libc::SO_REUSEPORT,
-                reuse as c_int,
-            )
-        }
-    }
-
-    /// Get the value of the `SO_REUSEPORT_LB` option on this socket.
-    ///
-    /// For more information about this option, see [`set_reuse_port_lb`].
-    ///
-    /// [`set_reuse_port_lb`]: crate::Socket::set_reuse_port_lb
-    #[cfg(all(feature = "all", target_os = "freebsd"))]
-    pub fn reuse_port_lb(&self) -> io::Result<bool> {
-        unsafe {
-            getsockopt::<c_int>(self.as_raw(), libc::SOL_SOCKET, libc::SO_REUSEPORT_LB)
-                .map(|reuse| reuse != 0)
-        }
-    }
-
-    /// Set value for the `SO_REUSEPORT_LB` option on this socket.
-    ///
-    /// This allows multiple programs or threads to bind to the same port and
-    /// incoming connections will be load balanced using a hash function.
-    #[cfg(all(feature = "all", target_os = "freebsd"))]
-    pub fn set_reuse_port_lb(&self, reuse: bool) -> io::Result<()> {
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                libc::SOL_SOCKET,
-                libc::SO_REUSEPORT_LB,
-                reuse as c_int,
-            )
-        }
-    }
-
-    /// Get the value of the `IP_FREEBIND` option on this socket.
-    ///
-    /// For more information about this option, see [`set_freebind`].
-    ///
-    /// [`set_freebind`]: crate::Socket::set_freebind
-    #[cfg(all(
-        feature = "all",
-        any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-        )))
-    )]
-    pub fn freebind(&self) -> io::Result<bool> {
-        unsafe {
-            getsockopt::<c_int>(self.as_raw(), libc::SOL_IP, libc::IP_FREEBIND)
-                .map(|freebind| freebind != 0)
-        }
-    }
-
-    /// Set value for the `IP_FREEBIND` option on this socket.
-    ///
-    /// If enabled, this boolean option allows binding to an IP address that is
-    /// nonlocal or does not (yet) exist.  This permits listening on a socket,
-    /// without requiring the underlying network interface or the specified
-    /// dynamic IP address to be up at the time that the application is trying
-    /// to bind to it.
-    #[cfg(all(
-        feature = "all",
-        any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(target_os = "android", target_os = "fuchsia", target_os = "linux")
-        )))
-    )]
-    pub fn set_freebind(&self, freebind: bool) -> io::Result<()> {
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                libc::SOL_IP,
-                libc::IP_FREEBIND,
-                freebind as c_int,
-            )
-        }
-    }
-
-    /// Get the value of the `IPV6_FREEBIND` option on this socket.
-    ///
-    /// This is an IPv6 counterpart of `IP_FREEBIND` socket option on
-    /// Android/Linux. For more information about this option, see
-    /// [`set_freebind`].
-    ///
-    /// [`set_freebind`]: crate::Socket::set_freebind
-    #[cfg(all(feature = "all", any(target_os = "android", target_os = "linux")))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(feature = "all", any(target_os = "android", target_os = "linux"))))
-    )]
-    pub fn freebind_ipv6(&self) -> io::Result<bool> {
-        unsafe {
-            getsockopt::<c_int>(self.as_raw(), libc::SOL_IPV6, libc::IPV6_FREEBIND)
-                .map(|freebind| freebind != 0)
-        }
-    }
-
-    /// Set value for the `IPV6_FREEBIND` option on this socket.
-    ///
-    /// This is an IPv6 counterpart of `IP_FREEBIND` socket option on
-    /// Android/Linux. For more information about this option, see
-    /// [`set_freebind`].
-    ///
-    /// [`set_freebind`]: crate::Socket::set_freebind
-    ///
-    /// # Examples
-    ///
-    /// On Linux:
-    ///
-    /// ```
-    /// use socket2::{Domain, Socket, Type};
-    /// use std::io::{self, Error, ErrorKind};
-    ///
-    /// fn enable_freebind(socket: &Socket) -> io::Result<()> {
-    ///     match socket.domain()? {
-    ///         Domain::IPV4 => socket.set_freebind(true)?,
-    ///         Domain::IPV6 => socket.set_freebind_ipv6(true)?,
-    ///         _ => return Err(Error::new(ErrorKind::Other, "unsupported domain")),
-    ///     };
-    ///     Ok(())
-    /// }
-    ///
-    /// # fn main() -> io::Result<()> {
-    /// #     let socket = Socket::new(Domain::IPV6, Type::STREAM, None)?;
-    /// #     enable_freebind(&socket)
-    /// # }
-    /// ```
-    #[cfg(all(feature = "all", any(target_os = "android", target_os = "linux")))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(feature = "all", any(target_os = "android", target_os = "linux"))))
-    )]
-    pub fn set_freebind_ipv6(&self, freebind: bool) -> io::Result<()> {
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                libc::SOL_IPV6,
-                libc::IPV6_FREEBIND,
-                freebind as c_int,
-            )
-        }
-    }
-
-    /// Copies data between a `file` and this socket using the `sendfile(2)`
-    /// system call. Because this copying is done within the kernel,
-    /// `sendfile()` is more efficient than the combination of `read(2)` and
-    /// `write(2)`, which would require transferring data to and from user
-    /// space.
-    ///
-    /// Different OSs support different kinds of `file`s, see the OS
-    /// documentation for what kind of files are supported. Generally *regular*
-    /// files are supported by all OSs.
-    #[doc = man_links!(unix: sendfile(2))]
-    ///
-    /// The `offset` is the absolute offset into the `file` to use as starting
-    /// point.
-    ///
-    /// Depending on the OS this function *may* change the offset of `file`. For
-    /// the best results reset the offset of the file before using it again.
-    ///
-    /// The `length` determines how many bytes to send, where a length of `None`
-    /// means it will try to send all bytes.
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "aix",
-            target_os = "android",
-            target_os = "freebsd",
-            target_os = "ios",
-            target_os = "visionos",
-            target_os = "linux",
-            target_os = "macos",
-            target_os = "tvos",
-            target_os = "watchos",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "aix",
-                target_os = "android",
-                target_os = "freebsd",
-                target_os = "ios",
-                target_os = "visionos",
-                target_os = "linux",
-                target_os = "macos",
-                target_os = "tvos",
-                target_os = "watchos",
-            )
-        )))
-    )]
-    pub fn sendfile<F>(
-        &self,
-        file: &F,
-        offset: usize,
-        length: Option<NonZeroUsize>,
-    ) -> io::Result<usize>
-    where
-        F: AsRawFd,
-    {
-        self._sendfile(file.as_raw_fd(), offset as _, length)
-    }
-
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "ios",
-            target_os = "visionos",
-            target_os = "macos",
-            target_os = "tvos",
-            target_os = "watchos",
-        )
-    ))]
-    fn _sendfile(
-        &self,
-        file: RawFd,
-        offset: libc::off_t,
-        length: Option<NonZeroUsize>,
-    ) -> io::Result<usize> {
-        // On macOS `length` is value-result parameter. It determines the number
-        // of bytes to write and returns the number of bytes written.
-        let mut length = match length {
-            Some(n) => n.get() as libc::off_t,
-            // A value of `0` means send all bytes.
-            None => 0,
-        };
-        syscall!(sendfile(
-            file,
-            self.as_raw(),
-            offset,
-            &mut length,
-            ptr::null_mut(),
-            0,
-        ))
-        .map(|_| length as usize)
-    }
-
-    #[cfg(all(feature = "all", any(target_os = "android", target_os = "linux")))]
-    fn _sendfile(
-        &self,
-        file: RawFd,
-        offset: libc::off_t,
-        length: Option<NonZeroUsize>,
-    ) -> io::Result<usize> {
-        let count = match length {
-            Some(n) => n.get() as libc::size_t,
-            // The maximum the Linux kernel will write in a single call.
-            None => 0x7ffff000, // 2,147,479,552 bytes.
-        };
-        let mut offset = offset;
-        syscall!(sendfile(self.as_raw(), file, &mut offset, count)).map(|n| n as usize)
-    }
-
-    #[cfg(all(feature = "all", target_os = "freebsd"))]
-    fn _sendfile(
-        &self,
-        file: RawFd,
-        offset: libc::off_t,
-        length: Option<NonZeroUsize>,
-    ) -> io::Result<usize> {
-        let nbytes = match length {
-            Some(n) => n.get() as libc::size_t,
-            // A value of `0` means send all bytes.
-            None => 0,
-        };
-        let mut sbytes: libc::off_t = 0;
-        syscall!(sendfile(
-            file,
-            self.as_raw(),
-            offset,
-            nbytes,
-            ptr::null_mut(),
-            &mut sbytes,
-            0,
-        ))
-        .map(|_| sbytes as usize)
-    }
-
-    #[cfg(all(feature = "all", target_os = "aix"))]
-    fn _sendfile(
-        &self,
-        file: RawFd,
-        offset: libc::off_t,
-        length: Option<NonZeroUsize>,
-    ) -> io::Result<usize> {
-        let nbytes = match length {
-            Some(n) => n.get() as i64,
-            None => -1,
-        };
-        let mut params = libc::sf_parms {
-            header_data: ptr::null_mut(),
-            header_length: 0,
-            file_descriptor: file,
-            file_size: 0,
-            file_offset: offset as u64,
-            file_bytes: nbytes,
-            trailer_data: ptr::null_mut(),
-            trailer_length: 0,
-            bytes_sent: 0,
-        };
-        // AIX doesn't support SF_REUSE, socket will be closed after successful transmission.
-        syscall!(send_file(
-            &mut self.as_raw() as *mut _,
-            &mut params as *mut _,
-            libc::SF_CLOSE as libc::c_uint,
-        ))
-        .map(|_| params.bytes_sent as usize)
-    }
-
-    /// Set the value of the `TCP_USER_TIMEOUT` option on this socket.
-    ///
-    /// If set, this specifies the maximum amount of time that transmitted data may remain
-    /// unacknowledged or buffered data may remain untransmitted before TCP will forcibly close the
-    /// corresponding connection.
-    ///
-    /// Setting `timeout` to `None` or a zero duration causes the system default timeouts to
-    /// be used. If `timeout` in milliseconds is larger than `c_uint::MAX`, the timeout is clamped
-    /// to `c_uint::MAX`. For example, when `c_uint` is a 32-bit value, this limits the timeout to
-    /// approximately 49.71 days.
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "android",
-            target_os = "fuchsia",
-            target_os = "linux",
-            target_os = "cygwin",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "android",
-                target_os = "fuchsia",
-                target_os = "linux",
-                target_os = "cygwin"
-            )
-        )))
-    )]
-    pub fn set_tcp_user_timeout(&self, timeout: Option<Duration>) -> io::Result<()> {
-        let timeout = timeout.map_or(0, |to| {
-            min(to.as_millis(), libc::c_uint::MAX as u128) as libc::c_uint
-        });
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                libc::IPPROTO_TCP,
-                libc::TCP_USER_TIMEOUT,
-                timeout,
-            )
-        }
-    }
-
-    /// Get the value of the `TCP_USER_TIMEOUT` option on this socket.
-    ///
-    /// For more information about this option, see [`set_tcp_user_timeout`].
-    ///
-    /// [`set_tcp_user_timeout`]: crate::Socket::set_tcp_user_timeout
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "android",
-            target_os = "fuchsia",
-            target_os = "linux",
-            target_os = "cygwin",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "android",
-                target_os = "fuchsia",
-                target_os = "linux",
-                target_os = "cygwin"
-            )
-        )))
-    )]
-    pub fn tcp_user_timeout(&self) -> io::Result<Option<Duration>> {
-        unsafe {
-            getsockopt::<libc::c_uint>(self.as_raw(), libc::IPPROTO_TCP, libc::TCP_USER_TIMEOUT)
-                .map(|millis| {
-                    if millis == 0 {
-                        None
-                    } else {
-                        Some(Duration::from_millis(millis as u64))
-                    }
-                })
-        }
-    }
-
-    /// Attach Berkeley Packet Filter(BPF) on this socket.
-    ///
-    /// BPF allows a user-space program to attach a filter onto any socket
-    /// and allow or disallow certain types of data to come through the socket.
-    ///
-    /// For more information about this option, see [filter](https://www.kernel.org/doc/html/v5.12/networking/filter.html)
-    #[cfg(all(feature = "all", any(target_os = "linux", target_os = "android")))]
-    pub fn attach_filter(&self, filters: &[libc::sock_filter]) -> io::Result<()> {
-        let prog = libc::sock_fprog {
-            len: filters.len() as u16,
-            filter: filters.as_ptr() as *mut _,
-        };
-
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                libc::SOL_SOCKET,
-                libc::SO_ATTACH_FILTER,
-                prog,
-            )
-        }
-    }
-
-    /// Detach Berkeley Packet Filter(BPF) from this socket.
-    ///
-    /// For more information about this option, see [`attach_filter`]
-    ///
-    /// [`attach_filter`]: crate::Socket::attach_filter
-    #[cfg(all(feature = "all", any(target_os = "linux", target_os = "android")))]
-    pub fn detach_filter(&self) -> io::Result<()> {
-        unsafe { setsockopt(self.as_raw(), libc::SOL_SOCKET, libc::SO_DETACH_FILTER, 0) }
-    }
-
-    /// Gets the value for the `SO_COOKIE` option on this socket.
-    ///
-    /// The socket cookie is a unique, kernel-managed identifier tied to each socket.
-    /// Therefore, there is no corresponding `set` helper.
-    ///
-    /// For more information about this option, see [Linux patch](https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=5daab9db7b65df87da26fd8cfa695fb9546a1ddb)
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn cookie(&self) -> io::Result<u64> {
-        unsafe { getsockopt::<libc::c_ulonglong>(self.as_raw(), libc::SOL_SOCKET, libc::SO_COOKIE) }
-    }
-
-    /// Get the value of the `IPV6_TCLASS` option for this socket.
-    ///
-    /// For more information about this option, see [`set_tclass_v6`].
-    ///
-    /// [`set_tclass_v6`]: crate::Socket::set_tclass_v6
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "android",
-            target_os = "dragonfly",
-            target_os = "freebsd",
-            target_os = "fuchsia",
-            target_os = "linux",
-            target_os = "macos",
-            target_os = "netbsd",
-            target_os = "openbsd",
-            target_os = "cygwin",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "android",
-                target_os = "dragonfly",
-                target_os = "freebsd",
-                target_os = "fuchsia",
-                target_os = "linux",
-                target_os = "macos",
-                target_os = "netbsd",
-                target_os = "openbsd"
-            )
-        )))
-    )]
-    pub fn tclass_v6(&self) -> io::Result<u32> {
-        unsafe {
-            getsockopt::<c_int>(self.as_raw(), IPPROTO_IPV6, libc::IPV6_TCLASS)
-                .map(|tclass| tclass as u32)
-        }
-    }
-
-    /// Set the value of the `IPV6_TCLASS` option for this socket.
-    ///
-    /// Specifies the traffic class field that is used in every packets
-    /// sent from this socket.
-    #[cfg(all(
-        feature = "all",
-        any(
-            target_os = "android",
-            target_os = "dragonfly",
-            target_os = "freebsd",
-            target_os = "fuchsia",
-            target_os = "linux",
-            target_os = "macos",
-            target_os = "netbsd",
-            target_os = "openbsd",
-            target_os = "cygwin",
-        )
-    ))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(
-            feature = "all",
-            any(
-                target_os = "android",
-                target_os = "dragonfly",
-                target_os = "freebsd",
-                target_os = "fuchsia",
-                target_os = "linux",
-                target_os = "macos",
-                target_os = "netbsd",
-                target_os = "openbsd"
-            )
-        )))
-    )]
-    pub fn set_tclass_v6(&self, tclass: u32) -> io::Result<()> {
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                IPPROTO_IPV6,
-                libc::IPV6_TCLASS,
-                tclass as c_int,
-            )
-        }
-    }
-
-    /// Get the value of the `TCP_CONGESTION` option for this socket.
-    ///
-    /// For more information about this option, see [`set_tcp_congestion`].
-    ///
-    /// [`set_tcp_congestion`]: crate::Socket::set_tcp_congestion
-    #[cfg(all(feature = "all", any(target_os = "freebsd", target_os = "linux")))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(feature = "all", any(target_os = "freebsd", target_os = "linux"))))
-    )]
-    pub fn tcp_congestion(&self) -> io::Result<Vec<u8>> {
-        let mut payload: [u8; TCP_CA_NAME_MAX] = [0; TCP_CA_NAME_MAX];
-        let mut len = payload.len() as libc::socklen_t;
-        syscall!(getsockopt(
-            self.as_raw(),
-            IPPROTO_TCP,
-            libc::TCP_CONGESTION,
-            payload.as_mut_ptr().cast(),
-            &mut len,
-        ))
-        .map(|_| payload[..len as usize].to_vec())
-    }
-
-    /// Set the value of the `TCP_CONGESTION` option for this socket.
-    ///
-    /// Specifies the TCP congestion control algorithm to use for this socket.
-    ///
-    /// The value must be a valid TCP congestion control algorithm name of the
-    /// platform. For example, Linux may supports "reno", "cubic".
-    #[cfg(all(feature = "all", any(target_os = "freebsd", target_os = "linux")))]
-    #[cfg_attr(
-        docsrs,
-        doc(cfg(all(feature = "all", any(target_os = "freebsd", target_os = "linux"))))
-    )]
-    pub fn set_tcp_congestion(&self, tcp_ca_name: &[u8]) -> io::Result<()> {
-        syscall!(setsockopt(
-            self.as_raw(),
-            IPPROTO_TCP,
-            libc::TCP_CONGESTION,
-            tcp_ca_name.as_ptr() as *const _,
-            tcp_ca_name.len() as libc::socklen_t,
-        ))
-        .map(|_| ())
-    }
-
-    /// Set value for the `DCCP_SOCKOPT_SERVICE` option on this socket.
-    ///
-    /// Sets the DCCP service. The specification mandates use of service codes.
-    /// If this socket option is not set, the socket will fall back to 0 (which
-    /// means that no meaningful service code is present). On active sockets
-    /// this is set before [`connect`]. On passive sockets up to 32 service
-    /// codes can be set before calling [`bind`]
-    ///
-    /// [`connect`]: crate::Socket::connect
-    /// [`bind`]: crate::Socket::bind
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn set_dccp_service(&self, code: u32) -> io::Result<()> {
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                libc::SOL_DCCP,
-                libc::DCCP_SOCKOPT_SERVICE,
-                code,
-            )
-        }
-    }
-
-    /// Get the value of the `DCCP_SOCKOPT_SERVICE` option on this socket.
-    ///
-    /// For more information about this option see [`set_dccp_service`]
-    ///
-    /// [`set_dccp_service`]: crate::Socket::set_dccp_service
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn dccp_service(&self) -> io::Result<u32> {
-        unsafe { getsockopt(self.as_raw(), libc::SOL_DCCP, libc::DCCP_SOCKOPT_SERVICE) }
-    }
-
-    /// Set value for the `DCCP_SOCKOPT_CCID` option on this socket.
-    ///
-    /// This option sets both the TX and RX CCIDs at the same time.
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn set_dccp_ccid(&self, ccid: u8) -> io::Result<()> {
-        unsafe { setsockopt(self.as_raw(), libc::SOL_DCCP, libc::DCCP_SOCKOPT_CCID, ccid) }
-    }
-
-    /// Get the value of the `DCCP_SOCKOPT_TX_CCID` option on this socket.
-    ///
-    /// For more information about this option see [`set_dccp_ccid`].
-    ///
-    /// [`set_dccp_ccid`]: crate::Socket::set_dccp_ccid
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn dccp_tx_ccid(&self) -> io::Result<u32> {
-        unsafe { getsockopt(self.as_raw(), libc::SOL_DCCP, libc::DCCP_SOCKOPT_TX_CCID) }
-    }
-
-    /// Get the value of the `DCCP_SOCKOPT_RX_CCID` option on this socket.
-    ///
-    /// For more information about this option see [`set_dccp_ccid`].
-    ///
-    /// [`set_dccp_ccid`]: crate::Socket::set_dccp_ccid
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn dccp_xx_ccid(&self) -> io::Result<u32> {
-        unsafe { getsockopt(self.as_raw(), libc::SOL_DCCP, libc::DCCP_SOCKOPT_RX_CCID) }
-    }
-
-    /// Set value for the `DCCP_SOCKOPT_SERVER_TIMEWAIT` option on this socket.
-    ///
-    /// Enables a listening socket to hold timewait state when closing the
-    /// connection. This option must be set after `accept` returns.
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn set_dccp_server_timewait(&self, hold_timewait: bool) -> io::Result<()> {
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                libc::SOL_DCCP,
-                libc::DCCP_SOCKOPT_SERVER_TIMEWAIT,
-                hold_timewait as c_int,
-            )
-        }
-    }
-
-    /// Get the value of the `DCCP_SOCKOPT_SERVER_TIMEWAIT` option on this socket.
-    ///
-    /// For more information see [`set_dccp_server_timewait`]
-    ///
-    /// [`set_dccp_server_timewait`]: crate::Socket::set_dccp_server_timewait
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn dccp_server_timewait(&self) -> io::Result<bool> {
-        unsafe {
-            getsockopt(
-                self.as_raw(),
-                libc::SOL_DCCP,
-                libc::DCCP_SOCKOPT_SERVER_TIMEWAIT,
-            )
-        }
-    }
-
-    /// Set value for the `DCCP_SOCKOPT_SEND_CSCOV` option on this socket.
-    ///
-    /// Both this option and `DCCP_SOCKOPT_RECV_CSCOV` are used for setting the
-    /// partial checksum coverage. The default is that checksums always cover
-    /// the entire packet and that only fully covered application data is
-    /// accepted by the receiver. Hence, when using this feature on the sender,
-    /// it must be enabled at the receiver too, with suitable choice of CsCov.
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn set_dccp_send_cscov(&self, level: u32) -> io::Result<()> {
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                libc::SOL_DCCP,
-                libc::DCCP_SOCKOPT_SEND_CSCOV,
-                level,
-            )
-        }
-    }
-
-    /// Get the value of the `DCCP_SOCKOPT_SEND_CSCOV` option on this socket.
-    ///
-    /// For more information on this option see [`set_dccp_send_cscov`].
-    ///
-    /// [`set_dccp_send_cscov`]: crate::Socket::set_dccp_send_cscov
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn dccp_send_cscov(&self) -> io::Result<u32> {
-        unsafe { getsockopt(self.as_raw(), libc::SOL_DCCP, libc::DCCP_SOCKOPT_SEND_CSCOV) }
-    }
-
-    /// Set the value of the `DCCP_SOCKOPT_RECV_CSCOV` option on this socket.
-    ///
-    /// This option is only useful when combined with [`set_dccp_send_cscov`].
-    ///
-    /// [`set_dccp_send_cscov`]: crate::Socket::set_dccp_send_cscov
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn set_dccp_recv_cscov(&self, level: u32) -> io::Result<()> {
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                libc::SOL_DCCP,
-                libc::DCCP_SOCKOPT_RECV_CSCOV,
-                level,
-            )
-        }
-    }
-
-    /// Get the value of the `DCCP_SOCKOPT_RECV_CSCOV` option on this socket.
-    ///
-    /// For more information on this option see [`set_dccp_recv_cscov`].
-    ///
-    /// [`set_dccp_recv_cscov`]: crate::Socket::set_dccp_recv_cscov
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn dccp_recv_cscov(&self) -> io::Result<u32> {
-        unsafe { getsockopt(self.as_raw(), libc::SOL_DCCP, libc::DCCP_SOCKOPT_RECV_CSCOV) }
-    }
-
-    /// Set value for the `DCCP_SOCKOPT_QPOLICY_TXQLEN` option on this socket.
-    ///
-    /// This option sets the maximum length of the output queue. A zero value is
-    /// interpreted as unbounded queue length.
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn set_dccp_qpolicy_txqlen(&self, length: u32) -> io::Result<()> {
-        unsafe {
-            setsockopt(
-                self.as_raw(),
-                libc::SOL_DCCP,
-                libc::DCCP_SOCKOPT_QPOLICY_TXQLEN,
-                length,
-            )
-        }
-    }
-
-    /// Get the value of the `DCCP_SOCKOPT_QPOLICY_TXQLEN` on this socket.
-    ///
-    /// For more information on this option see [`set_dccp_qpolicy_txqlen`].
-    ///
-    /// [`set_dccp_qpolicy_txqlen`]: crate::Socket::set_dccp_qpolicy_txqlen
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn dccp_qpolicy_txqlen(&self) -> io::Result<u32> {
-        unsafe {
-            getsockopt(
-                self.as_raw(),
-                libc::SOL_DCCP,
-                libc::DCCP_SOCKOPT_QPOLICY_TXQLEN,
-            )
-        }
-    }
-
-    /// Get the value of the `DCCP_SOCKOPT_AVAILABLE_CCIDS` option on this socket.
-    ///
-    /// Returns the list of CCIDs supported by the endpoint.
-    ///
-    /// The parameter `N` is used to get the maximum number of supported
-    /// endpoints. The [documentation] recommends a minimum of four at the time
-    /// of writing.
-    ///
-    /// [documentation]: https://www.kernel.org/doc/html/latest/networking/dccp.html
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn dccp_available_ccids<const N: usize>(&self) -> io::Result<CcidEndpoints<N>> {
-        let mut endpoints = [0; N];
-        let mut length = endpoints.len() as libc::socklen_t;
-        syscall!(getsockopt(
-            self.as_raw(),
-            libc::SOL_DCCP,
-            libc::DCCP_SOCKOPT_AVAILABLE_CCIDS,
-            endpoints.as_mut_ptr().cast(),
-            &mut length,
-        ))?;
-        Ok(CcidEndpoints { endpoints, length })
-    }
-
-    /// Get the value of the `DCCP_SOCKOPT_GET_CUR_MPS` option on this socket.
-    ///
-    /// This option retrieves the current maximum packet size (application
-    /// payload size) in bytes.
-    #[cfg(all(feature = "all", target_os = "linux"))]
-    #[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-    pub fn dccp_cur_mps(&self) -> io::Result<u32> {
-        unsafe {
-            getsockopt(
-                self.as_raw(),
-                libc::SOL_DCCP,
-                libc::DCCP_SOCKOPT_GET_CUR_MPS,
-            )
-        }
-    }
-}
-
-/// See [`Socket::dccp_available_ccids`].
-#[cfg(all(feature = "all", target_os = "linux"))]
-#[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-#[derive(Debug)]
-pub struct CcidEndpoints<const N: usize> {
-    endpoints: [u8; N],
-    length: u32,
-}
-
-#[cfg(all(feature = "all", target_os = "linux"))]
-#[cfg_attr(docsrs, doc(cfg(all(feature = "all", target_os = "linux"))))]
-impl<const N: usize> std::ops::Deref for CcidEndpoints<N> {
-    type Target = [u8];
-
-    fn deref(&self) -> &[u8] {
-        &self.endpoints[0..self.length as usize]
-    }
-}
-
-#[cfg_attr(docsrs, doc(cfg(unix)))]
-impl AsFd for crate::Socket {
-    fn as_fd(&self) -> BorrowedFd<'_> {
-        // SAFETY: lifetime is bound by self.
-        unsafe { BorrowedFd::borrow_raw(self.as_raw()) }
-    }
-}
-
-#[cfg_attr(docsrs, doc(cfg(unix)))]
-impl AsRawFd for crate::Socket {
-    fn as_raw_fd(&self) -> c_int {
-        self.as_raw()
-    }
-}
-
-#[cfg_attr(docsrs, doc(cfg(unix)))]
-impl From<crate::Socket> for OwnedFd {
-    fn from(sock: crate::Socket) -> OwnedFd {
-        // SAFETY: sock.into_raw() always returns a valid fd.
-        unsafe { OwnedFd::from_raw_fd(sock.into_raw()) }
-    }
-}
-
-#[cfg_attr(docsrs, doc(cfg(unix)))]
-impl IntoRawFd for crate::Socket {
-    fn into_raw_fd(self) -> c_int {
-        self.into_raw()
-    }
-}
-
-#[cfg_attr(docsrs, doc(cfg(unix)))]
-impl From<OwnedFd> for crate::Socket {
-    fn from(fd: OwnedFd) -> crate::Socket {
-        // SAFETY: `OwnedFd` ensures the fd is valid.
-        unsafe { crate::Socket::from_raw_fd(fd.into_raw_fd()) }
-    }
-}
-
-#[cfg_attr(docsrs, doc(cfg(unix)))]
-impl FromRawFd for crate::Socket {
-    unsafe fn from_raw_fd(fd: c_int) -> crate::Socket {
-        crate::Socket::from_raw(fd)
-    }
-}
-
-#[cfg(feature = "all")]
-from!(UnixStream, crate::Socket);
-#[cfg(feature = "all")]
-from!(UnixListener, crate::Socket);
-#[cfg(feature = "all")]
-from!(UnixDatagram, crate::Socket);
-#[cfg(feature = "all")]
-from!(crate::Socket, UnixStream);
-#[cfg(feature = "all")]
-from!(crate::Socket, UnixListener);
-#[cfg(feature = "all")]
-from!(crate::Socket, UnixDatagram);
-
-#[test]
-fn in_addr_convertion() {
-    let ip = Ipv4Addr::new(127, 0, 0, 1);
-    let raw = to_in_addr(&ip);
-    // NOTE: `in_addr` is packed on NetBSD and it's unsafe to borrow.
-    let a = raw.s_addr;
-    assert_eq!(a, u32::from_ne_bytes([127, 0, 0, 1]));
-    assert_eq!(from_in_addr(raw), ip);
-
-    let ip = Ipv4Addr::new(127, 34, 4, 12);
-    let raw = to_in_addr(&ip);
-    let a = raw.s_addr;
-    assert_eq!(a, u32::from_ne_bytes([127, 34, 4, 12]));
-    assert_eq!(from_in_addr(raw), ip);
-}
-
-#[test]
-fn in6_addr_convertion() {
-    let ip = Ipv6Addr::new(0x2000, 1, 2, 3, 4, 5, 6, 7);
-    let raw = to_in6_addr(&ip);
-    let want = [32, 0, 0, 1, 0, 2, 0, 3, 0, 4, 0, 5, 0, 6, 0, 7];
-    assert_eq!(raw.s6_addr, want);
-    assert_eq!(from_in6_addr(raw), ip);
-}