Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1310 insertions, 0 deletions

diff --git a/third_party/rust/tokio/src/net/tcp/stream.rs b/third_party/rust/tokio/src/net/tcp/stream.rs
new file mode 100644
index 0000000000..ebb67b84d1
--- /dev/null
+++ b/third_party/rust/tokio/src/net/tcp/stream.rs
@@ -0,0 +1,1310 @@
+use crate::future::poll_fn;
+use crate::io::{AsyncRead, AsyncWrite, Interest, PollEvented, ReadBuf, Ready};
+use crate::net::tcp::split::{split, ReadHalf, WriteHalf};
+use crate::net::tcp::split_owned::{split_owned, OwnedReadHalf, OwnedWriteHalf};
+use crate::net::{to_socket_addrs, ToSocketAddrs};
+
+use std::convert::TryFrom;
+use std::fmt;
+use std::io;
+use std::net::{Shutdown, SocketAddr};
+use std::pin::Pin;
+use std::task::{Context, Poll};
+use std::time::Duration;
+
+cfg_io_util! {
+    use bytes::BufMut;
+}
+
+cfg_net! {
+    /// A TCP stream between a local and a remote socket.
+    ///
+    /// A TCP stream can either be created by connecting to an endpoint, via the
+    /// [`connect`] method, or by [accepting] a connection from a [listener]. A
+    /// TCP stream can also be created via the [`TcpSocket`] type.
+    ///
+    /// Reading and writing to a `TcpStream` is usually done using the
+    /// convenience methods found on the [`AsyncReadExt`] and [`AsyncWriteExt`]
+    /// traits.
+    ///
+    /// [`connect`]: method@TcpStream::connect
+    /// [accepting]: method@crate::net::TcpListener::accept
+    /// [listener]: struct@crate::net::TcpListener
+    /// [`TcpSocket`]: struct@crate::net::TcpSocket
+    /// [`AsyncReadExt`]: trait@crate::io::AsyncReadExt
+    /// [`AsyncWriteExt`]: trait@crate::io::AsyncWriteExt
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::net::TcpStream;
+    /// use tokio::io::AsyncWriteExt;
+    /// use std::error::Error;
+    ///
+    /// #[tokio::main]
+    /// async fn main() -> Result<(), Box<dyn Error>> {
+    ///     // Connect to a peer
+    ///     let mut stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    ///     // Write some data.
+    ///     stream.write_all(b"hello world!").await?;
+    ///
+    ///     Ok(())
+    /// }
+    /// ```
+    ///
+    /// The [`write_all`] method is defined on the [`AsyncWriteExt`] trait.
+    ///
+    /// [`write_all`]: fn@crate::io::AsyncWriteExt::write_all
+    /// [`AsyncWriteExt`]: trait@crate::io::AsyncWriteExt
+    ///
+    /// To shut down the stream in the write direction, you can call the
+    /// [`shutdown()`] method. This will cause the other peer to receive a read of
+    /// length 0, indicating that no more data will be sent. This only closes
+    /// the stream in one direction.
+    ///
+    /// [`shutdown()`]: fn@crate::io::AsyncWriteExt::shutdown
+    pub struct TcpStream {
+        io: PollEvented<mio::net::TcpStream>,
+    }
+}
+
+impl TcpStream {
+    /// Opens a TCP connection to a remote host.
+    ///
+    /// `addr` is an address of the remote host. Anything which implements the
+    /// [`ToSocketAddrs`] trait can be supplied as the address.  If `addr`
+    /// yields multiple addresses, connect will be attempted with each of the
+    /// addresses until a connection is successful. If none of the addresses
+    /// result in a successful connection, the error returned from the last
+    /// connection attempt (the last address) is returned.
+    ///
+    /// To configure the socket before connecting, you can use the [`TcpSocket`]
+    /// type.
+    ///
+    /// [`ToSocketAddrs`]: trait@crate::net::ToSocketAddrs
+    /// [`TcpSocket`]: struct@crate::net::TcpSocket
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::net::TcpStream;
+    /// use tokio::io::AsyncWriteExt;
+    /// use std::error::Error;
+    ///
+    /// #[tokio::main]
+    /// async fn main() -> Result<(), Box<dyn Error>> {
+    ///     // Connect to a peer
+    ///     let mut stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    ///     // Write some data.
+    ///     stream.write_all(b"hello world!").await?;
+    ///
+    ///     Ok(())
+    /// }
+    /// ```
+    ///
+    /// The [`write_all`] method is defined on the [`AsyncWriteExt`] trait.
+    ///
+    /// [`write_all`]: fn@crate::io::AsyncWriteExt::write_all
+    /// [`AsyncWriteExt`]: trait@crate::io::AsyncWriteExt
+    pub async fn connect<A: ToSocketAddrs>(addr: A) -> io::Result<TcpStream> {
+        let addrs = to_socket_addrs(addr).await?;
+
+        let mut last_err = None;
+
+        for addr in addrs {
+            match TcpStream::connect_addr(addr).await {
+                Ok(stream) => return Ok(stream),
+                Err(e) => last_err = Some(e),
+            }
+        }
+
+        Err(last_err.unwrap_or_else(|| {
+            io::Error::new(
+                io::ErrorKind::InvalidInput,
+                "could not resolve to any address",
+            )
+        }))
+    }
+
+    /// Establishes a connection to the specified `addr`.
+    async fn connect_addr(addr: SocketAddr) -> io::Result<TcpStream> {
+        let sys = mio::net::TcpStream::connect(addr)?;
+        TcpStream::connect_mio(sys).await
+    }
+
+    pub(crate) async fn connect_mio(sys: mio::net::TcpStream) -> io::Result<TcpStream> {
+        let stream = TcpStream::new(sys)?;
+
+        // Once we've connected, wait for the stream to be writable as
+        // that's when the actual connection has been initiated. Once we're
+        // writable we check for `take_socket_error` to see if the connect
+        // actually hit an error or not.
+        //
+        // If all that succeeded then we ship everything on up.
+        poll_fn(|cx| stream.io.registration().poll_write_ready(cx)).await?;
+
+        if let Some(e) = stream.io.take_error()? {
+            return Err(e);
+        }
+
+        Ok(stream)
+    }
+
+    pub(crate) fn new(connected: mio::net::TcpStream) -> io::Result<TcpStream> {
+        let io = PollEvented::new(connected)?;
+        Ok(TcpStream { io })
+    }
+
+    /// Creates new `TcpStream` from a `std::net::TcpStream`.
+    ///
+    /// This function is intended to be used to wrap a TCP stream from the
+    /// standard library in the Tokio equivalent. The conversion assumes nothing
+    /// about the underlying stream; it is left up to the user to set it in
+    /// non-blocking mode.
+    ///
+    /// # Examples
+    ///
+    /// ```rust,no_run
+    /// use std::error::Error;
+    /// use tokio::net::TcpStream;
+    ///
+    /// #[tokio::main]
+    /// async fn main() -> Result<(), Box<dyn Error>> {
+    ///     let std_stream = std::net::TcpStream::connect("127.0.0.1:34254")?;
+    ///     std_stream.set_nonblocking(true)?;
+    ///     let stream = TcpStream::from_std(std_stream)?;
+    ///     Ok(())
+    /// }
+    /// ```
+    ///
+    /// # Panics
+    ///
+    /// This function panics if thread-local runtime is not set.
+    ///
+    /// The runtime is usually set implicitly when this function is called
+    /// from a future driven by a tokio runtime, otherwise runtime can be set
+    /// explicitly with [`Runtime::enter`](crate::runtime::Runtime::enter) function.
+    pub fn from_std(stream: std::net::TcpStream) -> io::Result<TcpStream> {
+        let io = mio::net::TcpStream::from_std(stream);
+        let io = PollEvented::new(io)?;
+        Ok(TcpStream { io })
+    }
+
+    /// Turns a [`tokio::net::TcpStream`] into a [`std::net::TcpStream`].
+    ///
+    /// The returned [`std::net::TcpStream`] will have nonblocking mode set as `true`.
+    /// Use [`set_nonblocking`] to change the blocking mode if needed.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::error::Error;
+    /// use std::io::Read;
+    /// use tokio::net::TcpListener;
+    /// # use tokio::net::TcpStream;
+    /// # use tokio::io::AsyncWriteExt;
+    ///
+    /// #[tokio::main]
+    /// async fn main() -> Result<(), Box<dyn Error>> {
+    ///     let mut data = [0u8; 12];
+    ///     let listener = TcpListener::bind("127.0.0.1:34254").await?;
+    /// #   let handle = tokio::spawn(async {
+    /// #       let mut stream: TcpStream = TcpStream::connect("127.0.0.1:34254").await.unwrap();
+    /// #       stream.write(b"Hello world!").await.unwrap();
+    /// #   });
+    ///     let (tokio_tcp_stream, _) = listener.accept().await?;
+    ///     let mut std_tcp_stream = tokio_tcp_stream.into_std()?;
+    /// #   handle.await.expect("The task being joined has panicked");
+    ///     std_tcp_stream.set_nonblocking(false)?;
+    ///     std_tcp_stream.read_exact(&mut data)?;
+    /// #   assert_eq!(b"Hello world!", &data);
+    ///     Ok(())
+    /// }
+    /// ```
+    /// [`tokio::net::TcpStream`]: TcpStream
+    /// [`std::net::TcpStream`]: std::net::TcpStream
+    /// [`set_nonblocking`]: fn@std::net::TcpStream::set_nonblocking
+    pub fn into_std(self) -> io::Result<std::net::TcpStream> {
+        #[cfg(unix)]
+        {
+            use std::os::unix::io::{FromRawFd, IntoRawFd};
+            self.io
+                .into_inner()
+                .map(|io| io.into_raw_fd())
+                .map(|raw_fd| unsafe { std::net::TcpStream::from_raw_fd(raw_fd) })
+        }
+
+        #[cfg(windows)]
+        {
+            use std::os::windows::io::{FromRawSocket, IntoRawSocket};
+            self.io
+                .into_inner()
+                .map(|io| io.into_raw_socket())
+                .map(|raw_socket| unsafe { std::net::TcpStream::from_raw_socket(raw_socket) })
+        }
+    }
+
+    /// Returns the local address that this stream is bound to.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::net::TcpStream;
+    ///
+    /// # async fn dox() -> Result<(), Box<dyn std::error::Error>> {
+    /// let stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    /// println!("{:?}", stream.local_addr()?);
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn local_addr(&self) -> io::Result<SocketAddr> {
+        self.io.local_addr()
+    }
+
+    /// Returns the remote address that this stream is connected to.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::net::TcpStream;
+    ///
+    /// # async fn dox() -> Result<(), Box<dyn std::error::Error>> {
+    /// let stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    /// println!("{:?}", stream.peer_addr()?);
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn peer_addr(&self) -> io::Result<SocketAddr> {
+        self.io.peer_addr()
+    }
+
+    /// Attempts to receive data on the socket, without removing that data from
+    /// the queue, registering the current task for wakeup if data is not yet
+    /// available.
+    ///
+    /// Note that on multiple calls to `poll_peek`, `poll_read` or
+    /// `poll_read_ready`, only the `Waker` from the `Context` passed to the
+    /// most recent call is scheduled to receive a wakeup. (However,
+    /// `poll_write` retains a second, independent waker.)
+    ///
+    /// # Return value
+    ///
+    /// The function returns:
+    ///
+    /// * `Poll::Pending` if data is not yet available.
+    /// * `Poll::Ready(Ok(n))` if data is available. `n` is the number of bytes peeked.
+    /// * `Poll::Ready(Err(e))` if an error is encountered.
+    ///
+    /// # Errors
+    ///
+    /// This function may encounter any standard I/O error except `WouldBlock`.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::io::{self, ReadBuf};
+    /// use tokio::net::TcpStream;
+    ///
+    /// use futures::future::poll_fn;
+    ///
+    /// #[tokio::main]
+    /// async fn main() -> io::Result<()> {
+    ///     let stream = TcpStream::connect("127.0.0.1:8000").await?;
+    ///     let mut buf = [0; 10];
+    ///     let mut buf = ReadBuf::new(&mut buf);
+    ///
+    ///     poll_fn(|cx| {
+    ///         stream.poll_peek(cx, &mut buf)
+    ///     }).await?;
+    ///
+    ///     Ok(())
+    /// }
+    /// ```
+    pub fn poll_peek(
+        &self,
+        cx: &mut Context<'_>,
+        buf: &mut ReadBuf<'_>,
+    ) -> Poll<io::Result<usize>> {
+        loop {
+            let ev = ready!(self.io.registration().poll_read_ready(cx))?;
+
+            let b = unsafe {
+                &mut *(buf.unfilled_mut() as *mut [std::mem::MaybeUninit<u8>] as *mut [u8])
+            };
+
+            match self.io.peek(b) {
+                Ok(ret) => {
+                    unsafe { buf.assume_init(ret) };
+                    buf.advance(ret);
+                    return Poll::Ready(Ok(ret));
+                }
+                Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
+                    self.io.registration().clear_readiness(ev);
+                }
+                Err(e) => return Poll::Ready(Err(e)),
+            }
+        }
+    }
+
+    /// Waits for any of the requested ready states.
+    ///
+    /// This function is usually paired with `try_read()` or `try_write()`. It
+    /// can be used to concurrently read / write to the same socket on a single
+    /// task without splitting the socket.
+    ///
+    /// # Cancel safety
+    ///
+    /// This method is cancel safe. Once a readiness event occurs, the method
+    /// will continue to return immediately until the readiness event is
+    /// consumed by an attempt to read or write that fails with `WouldBlock` or
+    /// `Poll::Pending`.
+    ///
+    /// # Examples
+    ///
+    /// Concurrently read and write to the stream on the same task without
+    /// splitting.
+    ///
+    /// ```no_run
+    /// use tokio::io::Interest;
+    /// use tokio::net::TcpStream;
+    /// use std::error::Error;
+    /// use std::io;
+    ///
+    /// #[tokio::main]
+    /// async fn main() -> Result<(), Box<dyn Error>> {
+    ///     let stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    ///     loop {
+    ///         let ready = stream.ready(Interest::READABLE | Interest::WRITABLE).await?;
+    ///
+    ///         if ready.is_readable() {
+    ///             let mut data = vec![0; 1024];
+    ///             // Try to read data, this may still fail with `WouldBlock`
+    ///             // if the readiness event is a false positive.
+    ///             match stream.try_read(&mut data) {
+    ///                 Ok(n) => {
+    ///                     println!("read {} bytes", n);
+    ///                 }
+    ///                 Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
+    ///                     continue;
+    ///                 }
+    ///                 Err(e) => {
+    ///                     return Err(e.into());
+    ///                 }
+    ///             }
+    ///
+    ///         }
+    ///
+    ///         if ready.is_writable() {
+    ///             // Try to write data, this may still fail with `WouldBlock`
+    ///             // if the readiness event is a false positive.
+    ///             match stream.try_write(b"hello world") {
+    ///                 Ok(n) => {
+    ///                     println!("write {} bytes", n);
+    ///                 }
+    ///                 Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
+    ///                     continue
+    ///                 }
+    ///                 Err(e) => {
+    ///                     return Err(e.into());
+    ///                 }
+    ///             }
+    ///         }
+    ///     }
+    /// }
+    /// ```
+    pub async fn ready(&self, interest: Interest) -> io::Result<Ready> {
+        let event = self.io.registration().readiness(interest).await?;
+        Ok(event.ready)
+    }
+
+    /// Waits for the socket to become readable.
+    ///
+    /// This function is equivalent to `ready(Interest::READABLE)` and is usually
+    /// paired with `try_read()`.
+    ///
+    /// # Cancel safety
+    ///
+    /// This method is cancel safe. Once a readiness event occurs, the method
+    /// will continue to return immediately until the readiness event is
+    /// consumed by an attempt to read that fails with `WouldBlock` or
+    /// `Poll::Pending`.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::net::TcpStream;
+    /// use std::error::Error;
+    /// use std::io;
+    ///
+    /// #[tokio::main]
+    /// async fn main() -> Result<(), Box<dyn Error>> {
+    ///     // Connect to a peer
+    ///     let stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    ///     let mut msg = vec![0; 1024];
+    ///
+    ///     loop {
+    ///         // Wait for the socket to be readable
+    ///         stream.readable().await?;
+    ///
+    ///         // Try to read data, this may still fail with `WouldBlock`
+    ///         // if the readiness event is a false positive.
+    ///         match stream.try_read(&mut msg) {
+    ///             Ok(n) => {
+    ///                 msg.truncate(n);
+    ///                 break;
+    ///             }
+    ///             Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
+    ///                 continue;
+    ///             }
+    ///             Err(e) => {
+    ///                 return Err(e.into());
+    ///             }
+    ///         }
+    ///     }
+    ///
+    ///     println!("GOT = {:?}", msg);
+    ///     Ok(())
+    /// }
+    /// ```
+    pub async fn readable(&self) -> io::Result<()> {
+        self.ready(Interest::READABLE).await?;
+        Ok(())
+    }
+
+    /// Polls for read readiness.
+    ///
+    /// If the tcp stream is not currently ready for reading, this method will
+    /// store a clone of the `Waker` from the provided `Context`. When the tcp
+    /// stream becomes ready for reading, `Waker::wake` will be called on the
+    /// waker.
+    ///
+    /// Note that on multiple calls to `poll_read_ready`, `poll_read` or
+    /// `poll_peek`, only the `Waker` from the `Context` passed to the most
+    /// recent call is scheduled to receive a wakeup. (However,
+    /// `poll_write_ready` retains a second, independent waker.)
+    ///
+    /// This function is intended for cases where creating and pinning a future
+    /// via [`readable`] is not feasible. Where possible, using [`readable`] is
+    /// preferred, as this supports polling from multiple tasks at once.
+    ///
+    /// # Return value
+    ///
+    /// The function returns:
+    ///
+    /// * `Poll::Pending` if the tcp stream is not ready for reading.
+    /// * `Poll::Ready(Ok(()))` if the tcp stream is ready for reading.
+    /// * `Poll::Ready(Err(e))` if an error is encountered.
+    ///
+    /// # Errors
+    ///
+    /// This function may encounter any standard I/O error except `WouldBlock`.
+    ///
+    /// [`readable`]: method@Self::readable
+    pub fn poll_read_ready(&self, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
+        self.io.registration().poll_read_ready(cx).map_ok(|_| ())
+    }
+
+    /// Tries to read data from the stream into the provided buffer, returning how
+    /// many bytes were read.
+    ///
+    /// Receives any pending data from the socket but does not wait for new data
+    /// to arrive. On success, returns the number of bytes read. Because
+    /// `try_read()` is non-blocking, the buffer does not have to be stored by
+    /// the async task and can exist entirely on the stack.
+    ///
+    /// Usually, [`readable()`] or [`ready()`] is used with this function.
+    ///
+    /// [`readable()`]: TcpStream::readable()
+    /// [`ready()`]: TcpStream::ready()
+    ///
+    /// # Return
+    ///
+    /// If data is successfully read, `Ok(n)` is returned, where `n` is the
+    /// number of bytes read. `Ok(0)` indicates the stream's read half is closed
+    /// and will no longer yield data. If the stream is not ready to read data
+    /// `Err(io::ErrorKind::WouldBlock)` is returned.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::net::TcpStream;
+    /// use std::error::Error;
+    /// use std::io;
+    ///
+    /// #[tokio::main]
+    /// async fn main() -> Result<(), Box<dyn Error>> {
+    ///     // Connect to a peer
+    ///     let stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    ///     loop {
+    ///         // Wait for the socket to be readable
+    ///         stream.readable().await?;
+    ///
+    ///         // Creating the buffer **after** the `await` prevents it from
+    ///         // being stored in the async task.
+    ///         let mut buf = [0; 4096];
+    ///
+    ///         // Try to read data, this may still fail with `WouldBlock`
+    ///         // if the readiness event is a false positive.
+    ///         match stream.try_read(&mut buf) {
+    ///             Ok(0) => break,
+    ///             Ok(n) => {
+    ///                 println!("read {} bytes", n);
+    ///             }
+    ///             Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
+    ///                 continue;
+    ///             }
+    ///             Err(e) => {
+    ///                 return Err(e.into());
+    ///             }
+    ///         }
+    ///     }
+    ///
+    ///     Ok(())
+    /// }
+    /// ```
+    pub fn try_read(&self, buf: &mut [u8]) -> io::Result<usize> {
+        use std::io::Read;
+
+        self.io
+            .registration()
+            .try_io(Interest::READABLE, || (&*self.io).read(buf))
+    }
+
+    /// Tries to read data from the stream into the provided buffers, returning
+    /// how many bytes were read.
+    ///
+    /// Data is copied to fill each buffer in order, with the final buffer
+    /// written to possibly being only partially filled. This method behaves
+    /// equivalently to a single call to [`try_read()`] with concatenated
+    /// buffers.
+    ///
+    /// Receives any pending data from the socket but does not wait for new data
+    /// to arrive. On success, returns the number of bytes read. Because
+    /// `try_read_vectored()` is non-blocking, the buffer does not have to be
+    /// stored by the async task and can exist entirely on the stack.
+    ///
+    /// Usually, [`readable()`] or [`ready()`] is used with this function.
+    ///
+    /// [`try_read()`]: TcpStream::try_read()
+    /// [`readable()`]: TcpStream::readable()
+    /// [`ready()`]: TcpStream::ready()
+    ///
+    /// # Return
+    ///
+    /// If data is successfully read, `Ok(n)` is returned, where `n` is the
+    /// number of bytes read. `Ok(0)` indicates the stream's read half is closed
+    /// and will no longer yield data. If the stream is not ready to read data
+    /// `Err(io::ErrorKind::WouldBlock)` is returned.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::net::TcpStream;
+    /// use std::error::Error;
+    /// use std::io::{self, IoSliceMut};
+    ///
+    /// #[tokio::main]
+    /// async fn main() -> Result<(), Box<dyn Error>> {
+    ///     // Connect to a peer
+    ///     let stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    ///     loop {
+    ///         // Wait for the socket to be readable
+    ///         stream.readable().await?;
+    ///
+    ///         // Creating the buffer **after** the `await` prevents it from
+    ///         // being stored in the async task.
+    ///         let mut buf_a = [0; 512];
+    ///         let mut buf_b = [0; 1024];
+    ///         let mut bufs = [
+    ///             IoSliceMut::new(&mut buf_a),
+    ///             IoSliceMut::new(&mut buf_b),
+    ///         ];
+    ///
+    ///         // Try to read data, this may still fail with `WouldBlock`
+    ///         // if the readiness event is a false positive.
+    ///         match stream.try_read_vectored(&mut bufs) {
+    ///             Ok(0) => break,
+    ///             Ok(n) => {
+    ///                 println!("read {} bytes", n);
+    ///             }
+    ///             Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
+    ///                 continue;
+    ///             }
+    ///             Err(e) => {
+    ///                 return Err(e.into());
+    ///             }
+    ///         }
+    ///     }
+    ///
+    ///     Ok(())
+    /// }
+    /// ```
+    pub fn try_read_vectored(&self, bufs: &mut [io::IoSliceMut<'_>]) -> io::Result<usize> {
+        use std::io::Read;
+
+        self.io
+            .registration()
+            .try_io(Interest::READABLE, || (&*self.io).read_vectored(bufs))
+    }
+
+    cfg_io_util! {
+        /// Tries to read data from the stream into the provided buffer, advancing the
+        /// buffer's internal cursor, returning how many bytes were read.
+        ///
+        /// Receives any pending data from the socket but does not wait for new data
+        /// to arrive. On success, returns the number of bytes read. Because
+        /// `try_read_buf()` is non-blocking, the buffer does not have to be stored by
+        /// the async task and can exist entirely on the stack.
+        ///
+        /// Usually, [`readable()`] or [`ready()`] is used with this function.
+        ///
+        /// [`readable()`]: TcpStream::readable()
+        /// [`ready()`]: TcpStream::ready()
+        ///
+        /// # Return
+        ///
+        /// If data is successfully read, `Ok(n)` is returned, where `n` is the
+        /// number of bytes read. `Ok(0)` indicates the stream's read half is closed
+        /// and will no longer yield data. If the stream is not ready to read data
+        /// `Err(io::ErrorKind::WouldBlock)` is returned.
+        ///
+        /// # Examples
+        ///
+        /// ```no_run
+        /// use tokio::net::TcpStream;
+        /// use std::error::Error;
+        /// use std::io;
+        ///
+        /// #[tokio::main]
+        /// async fn main() -> Result<(), Box<dyn Error>> {
+        ///     // Connect to a peer
+        ///     let stream = TcpStream::connect("127.0.0.1:8080").await?;
+        ///
+        ///     loop {
+        ///         // Wait for the socket to be readable
+        ///         stream.readable().await?;
+        ///
+        ///         let mut buf = Vec::with_capacity(4096);
+        ///
+        ///         // Try to read data, this may still fail with `WouldBlock`
+        ///         // if the readiness event is a false positive.
+        ///         match stream.try_read_buf(&mut buf) {
+        ///             Ok(0) => break,
+        ///             Ok(n) => {
+        ///                 println!("read {} bytes", n);
+        ///             }
+        ///             Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
+        ///                 continue;
+        ///             }
+        ///             Err(e) => {
+        ///                 return Err(e.into());
+        ///             }
+        ///         }
+        ///     }
+        ///
+        ///     Ok(())
+        /// }
+        /// ```
+        pub fn try_read_buf<B: BufMut>(&self, buf: &mut B) -> io::Result<usize> {
+            self.io.registration().try_io(Interest::READABLE, || {
+                use std::io::Read;
+
+                let dst = buf.chunk_mut();
+                let dst =
+                    unsafe { &mut *(dst as *mut _ as *mut [std::mem::MaybeUninit<u8>] as *mut [u8]) };
+
+                // Safety: We trust `TcpStream::read` to have filled up `n` bytes in the
+                // buffer.
+                let n = (&*self.io).read(dst)?;
+
+                unsafe {
+                    buf.advance_mut(n);
+                }
+
+                Ok(n)
+            })
+        }
+    }
+
+    /// Waits for the socket to become writable.
+    ///
+    /// This function is equivalent to `ready(Interest::WRITABLE)` and is usually
+    /// paired with `try_write()`.
+    ///
+    /// # Cancel safety
+    ///
+    /// This method is cancel safe. Once a readiness event occurs, the method
+    /// will continue to return immediately until the readiness event is
+    /// consumed by an attempt to write that fails with `WouldBlock` or
+    /// `Poll::Pending`.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::net::TcpStream;
+    /// use std::error::Error;
+    /// use std::io;
+    ///
+    /// #[tokio::main]
+    /// async fn main() -> Result<(), Box<dyn Error>> {
+    ///     // Connect to a peer
+    ///     let stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    ///     loop {
+    ///         // Wait for the socket to be writable
+    ///         stream.writable().await?;
+    ///
+    ///         // Try to write data, this may still fail with `WouldBlock`
+    ///         // if the readiness event is a false positive.
+    ///         match stream.try_write(b"hello world") {
+    ///             Ok(n) => {
+    ///                 break;
+    ///             }
+    ///             Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
+    ///                 continue;
+    ///             }
+    ///             Err(e) => {
+    ///                 return Err(e.into());
+    ///             }
+    ///         }
+    ///     }
+    ///
+    ///     Ok(())
+    /// }
+    /// ```
+    pub async fn writable(&self) -> io::Result<()> {
+        self.ready(Interest::WRITABLE).await?;
+        Ok(())
+    }
+
+    /// Polls for write readiness.
+    ///
+    /// If the tcp stream is not currently ready for writing, this method will
+    /// store a clone of the `Waker` from the provided `Context`. When the tcp
+    /// stream becomes ready for writing, `Waker::wake` will be called on the
+    /// waker.
+    ///
+    /// Note that on multiple calls to `poll_write_ready` or `poll_write`, only
+    /// the `Waker` from the `Context` passed to the most recent call is
+    /// scheduled to receive a wakeup. (However, `poll_read_ready` retains a
+    /// second, independent waker.)
+    ///
+    /// This function is intended for cases where creating and pinning a future
+    /// via [`writable`] is not feasible. Where possible, using [`writable`] is
+    /// preferred, as this supports polling from multiple tasks at once.
+    ///
+    /// # Return value
+    ///
+    /// The function returns:
+    ///
+    /// * `Poll::Pending` if the tcp stream is not ready for writing.
+    /// * `Poll::Ready(Ok(()))` if the tcp stream is ready for writing.
+    /// * `Poll::Ready(Err(e))` if an error is encountered.
+    ///
+    /// # Errors
+    ///
+    /// This function may encounter any standard I/O error except `WouldBlock`.
+    ///
+    /// [`writable`]: method@Self::writable
+    pub fn poll_write_ready(&self, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
+        self.io.registration().poll_write_ready(cx).map_ok(|_| ())
+    }
+
+    /// Try to write a buffer to the stream, returning how many bytes were
+    /// written.
+    ///
+    /// The function will attempt to write the entire contents of `buf`, but
+    /// only part of the buffer may be written.
+    ///
+    /// This function is usually paired with `writable()`.
+    ///
+    /// # Return
+    ///
+    /// If data is successfully written, `Ok(n)` is returned, where `n` is the
+    /// number of bytes written. If the stream is not ready to write data,
+    /// `Err(io::ErrorKind::WouldBlock)` is returned.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::net::TcpStream;
+    /// use std::error::Error;
+    /// use std::io;
+    ///
+    /// #[tokio::main]
+    /// async fn main() -> Result<(), Box<dyn Error>> {
+    ///     // Connect to a peer
+    ///     let stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    ///     loop {
+    ///         // Wait for the socket to be writable
+    ///         stream.writable().await?;
+    ///
+    ///         // Try to write data, this may still fail with `WouldBlock`
+    ///         // if the readiness event is a false positive.
+    ///         match stream.try_write(b"hello world") {
+    ///             Ok(n) => {
+    ///                 break;
+    ///             }
+    ///             Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
+    ///                 continue;
+    ///             }
+    ///             Err(e) => {
+    ///                 return Err(e.into());
+    ///             }
+    ///         }
+    ///     }
+    ///
+    ///     Ok(())
+    /// }
+    /// ```
+    pub fn try_write(&self, buf: &[u8]) -> io::Result<usize> {
+        use std::io::Write;
+
+        self.io
+            .registration()
+            .try_io(Interest::WRITABLE, || (&*self.io).write(buf))
+    }
+
+    /// Tries to write several buffers to the stream, returning how many bytes
+    /// were written.
+    ///
+    /// Data is written from each buffer in order, with the final buffer read
+    /// from possible being only partially consumed. This method behaves
+    /// equivalently to a single call to [`try_write()`] with concatenated
+    /// buffers.
+    ///
+    /// This function is usually paired with `writable()`.
+    ///
+    /// [`try_write()`]: TcpStream::try_write()
+    ///
+    /// # Return
+    ///
+    /// If data is successfully written, `Ok(n)` is returned, where `n` is the
+    /// number of bytes written. If the stream is not ready to write data,
+    /// `Err(io::ErrorKind::WouldBlock)` is returned.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::net::TcpStream;
+    /// use std::error::Error;
+    /// use std::io;
+    ///
+    /// #[tokio::main]
+    /// async fn main() -> Result<(), Box<dyn Error>> {
+    ///     // Connect to a peer
+    ///     let stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    ///     let bufs = [io::IoSlice::new(b"hello "), io::IoSlice::new(b"world")];
+    ///
+    ///     loop {
+    ///         // Wait for the socket to be writable
+    ///         stream.writable().await?;
+    ///
+    ///         // Try to write data, this may still fail with `WouldBlock`
+    ///         // if the readiness event is a false positive.
+    ///         match stream.try_write_vectored(&bufs) {
+    ///             Ok(n) => {
+    ///                 break;
+    ///             }
+    ///             Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
+    ///                 continue;
+    ///             }
+    ///             Err(e) => {
+    ///                 return Err(e.into());
+    ///             }
+    ///         }
+    ///     }
+    ///
+    ///     Ok(())
+    /// }
+    /// ```
+    pub fn try_write_vectored(&self, bufs: &[io::IoSlice<'_>]) -> io::Result<usize> {
+        use std::io::Write;
+
+        self.io
+            .registration()
+            .try_io(Interest::WRITABLE, || (&*self.io).write_vectored(bufs))
+    }
+
+    /// Tries to read or write from the socket using a user-provided IO operation.
+    ///
+    /// If the socket is ready, the provided closure is called. The closure
+    /// should attempt to perform IO operation from the socket by manually
+    /// calling the appropriate syscall. If the operation fails because the
+    /// socket is not actually ready, then the closure should return a
+    /// `WouldBlock` error and the readiness flag is cleared. The return value
+    /// of the closure is then returned by `try_io`.
+    ///
+    /// If the socket is not ready, then the closure is not called
+    /// and a `WouldBlock` error is returned.
+    ///
+    /// The closure should only return a `WouldBlock` error if it has performed
+    /// an IO operation on the socket that failed due to the socket not being
+    /// ready. Returning a `WouldBlock` error in any other situation will
+    /// incorrectly clear the readiness flag, which can cause the socket to
+    /// behave incorrectly.
+    ///
+    /// The closure should not perform the IO operation using any of the methods
+    /// defined on the Tokio `TcpStream` type, as this will mess with the
+    /// readiness flag and can cause the socket to behave incorrectly.
+    ///
+    /// Usually, [`readable()`], [`writable()`] or [`ready()`] is used with this function.
+    ///
+    /// [`readable()`]: TcpStream::readable()
+    /// [`writable()`]: TcpStream::writable()
+    /// [`ready()`]: TcpStream::ready()
+    pub fn try_io<R>(
+        &self,
+        interest: Interest,
+        f: impl FnOnce() -> io::Result<R>,
+    ) -> io::Result<R> {
+        self.io.registration().try_io(interest, f)
+    }
+
+    /// Receives data on the socket from the remote address to which it is
+    /// connected, without removing that data from the queue. On success,
+    /// returns the number of bytes peeked.
+    ///
+    /// Successive calls return the same data. This is accomplished by passing
+    /// `MSG_PEEK` as a flag to the underlying recv system call.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::net::TcpStream;
+    /// use tokio::io::AsyncReadExt;
+    /// use std::error::Error;
+    ///
+    /// #[tokio::main]
+    /// async fn main() -> Result<(), Box<dyn Error>> {
+    ///     // Connect to a peer
+    ///     let mut stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    ///     let mut b1 = [0; 10];
+    ///     let mut b2 = [0; 10];
+    ///
+    ///     // Peek at the data
+    ///     let n = stream.peek(&mut b1).await?;
+    ///
+    ///     // Read the data
+    ///     assert_eq!(n, stream.read(&mut b2[..n]).await?);
+    ///     assert_eq!(&b1[..n], &b2[..n]);
+    ///
+    ///     Ok(())
+    /// }
+    /// ```
+    ///
+    /// The [`read`] method is defined on the [`AsyncReadExt`] trait.
+    ///
+    /// [`read`]: fn@crate::io::AsyncReadExt::read
+    /// [`AsyncReadExt`]: trait@crate::io::AsyncReadExt
+    pub async fn peek(&self, buf: &mut [u8]) -> io::Result<usize> {
+        self.io
+            .registration()
+            .async_io(Interest::READABLE, || self.io.peek(buf))
+            .await
+    }
+
+    /// Shuts down the read, write, or both halves of this connection.
+    ///
+    /// This function will cause all pending and future I/O on the specified
+    /// portions to return immediately with an appropriate value (see the
+    /// documentation of `Shutdown`).
+    pub(super) fn shutdown_std(&self, how: Shutdown) -> io::Result<()> {
+        self.io.shutdown(how)
+    }
+
+    /// Gets the value of the `TCP_NODELAY` option on this socket.
+    ///
+    /// For more information about this option, see [`set_nodelay`].
+    ///
+    /// [`set_nodelay`]: TcpStream::set_nodelay
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::net::TcpStream;
+    ///
+    /// # async fn dox() -> Result<(), Box<dyn std::error::Error>> {
+    /// let stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    /// println!("{:?}", stream.nodelay()?);
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn nodelay(&self) -> io::Result<bool> {
+        self.io.nodelay()
+    }
+
+    /// Sets the value of the `TCP_NODELAY` option on this socket.
+    ///
+    /// If set, this option disables the Nagle algorithm. This means that
+    /// segments are always sent as soon as possible, even if there is only a
+    /// small amount of data. When not set, data is buffered until there is a
+    /// sufficient amount to send out, thereby avoiding the frequent sending of
+    /// small packets.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::net::TcpStream;
+    ///
+    /// # async fn dox() -> Result<(), Box<dyn std::error::Error>> {
+    /// let stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    /// stream.set_nodelay(true)?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn set_nodelay(&self, nodelay: bool) -> io::Result<()> {
+        self.io.set_nodelay(nodelay)
+    }
+
+    /// Reads the linger duration for this socket by getting the `SO_LINGER`
+    /// option.
+    ///
+    /// For more information about this option, see [`set_linger`].
+    ///
+    /// [`set_linger`]: TcpStream::set_linger
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::net::TcpStream;
+    ///
+    /// # async fn dox() -> Result<(), Box<dyn std::error::Error>> {
+    /// let stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    /// println!("{:?}", stream.linger()?);
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn linger(&self) -> io::Result<Option<Duration>> {
+        socket2::SockRef::from(self).linger()
+    }
+
+    /// Sets the linger duration of this socket by setting the SO_LINGER option.
+    ///
+    /// This option controls the action taken when a stream has unsent messages and the stream is
+    /// closed. If SO_LINGER is set, the system shall block the process until it can transmit the
+    /// data or until the time expires.
+    ///
+    /// If SO_LINGER is not specified, and the stream is closed, the system handles the call in a
+    /// way that allows the process to continue as quickly as possible.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::net::TcpStream;
+    ///
+    /// # async fn dox() -> Result<(), Box<dyn std::error::Error>> {
+    /// let stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    /// stream.set_linger(None)?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn set_linger(&self, dur: Option<Duration>) -> io::Result<()> {
+        socket2::SockRef::from(self).set_linger(dur)
+    }
+
+    /// Gets the value of the `IP_TTL` option for this socket.
+    ///
+    /// For more information about this option, see [`set_ttl`].
+    ///
+    /// [`set_ttl`]: TcpStream::set_ttl
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::net::TcpStream;
+    ///
+    /// # async fn dox() -> Result<(), Box<dyn std::error::Error>> {
+    /// let stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    /// println!("{:?}", stream.ttl()?);
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn ttl(&self) -> io::Result<u32> {
+        self.io.ttl()
+    }
+
+    /// Sets the value for the `IP_TTL` option on this socket.
+    ///
+    /// This value sets the time-to-live field that is used in every packet sent
+    /// from this socket.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use tokio::net::TcpStream;
+    ///
+    /// # async fn dox() -> Result<(), Box<dyn std::error::Error>> {
+    /// let stream = TcpStream::connect("127.0.0.1:8080").await?;
+    ///
+    /// stream.set_ttl(123)?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    pub fn set_ttl(&self, ttl: u32) -> io::Result<()> {
+        self.io.set_ttl(ttl)
+    }
+
+    // These lifetime markers also appear in the generated documentation, and make
+    // it more clear that this is a *borrowed* split.
+    #[allow(clippy::needless_lifetimes)]
+    /// Splits a `TcpStream` into a read half and a write half, which can be used
+    /// to read and write the stream concurrently.
+    ///
+    /// This method is more efficient than [`into_split`], but the halves cannot be
+    /// moved into independently spawned tasks.
+    ///
+    /// [`into_split`]: TcpStream::into_split()
+    pub fn split<'a>(&'a mut self) -> (ReadHalf<'a>, WriteHalf<'a>) {
+        split(self)
+    }
+
+    /// Splits a `TcpStream` into a read half and a write half, which can be used
+    /// to read and write the stream concurrently.
+    ///
+    /// Unlike [`split`], the owned halves can be moved to separate tasks, however
+    /// this comes at the cost of a heap allocation.
+    ///
+    /// **Note:** Dropping the write half will shut down the write half of the TCP
+    /// stream. This is equivalent to calling [`shutdown()`] on the `TcpStream`.
+    ///
+    /// [`split`]: TcpStream::split()
+    /// [`shutdown()`]: fn@crate::io::AsyncWriteExt::shutdown
+    pub fn into_split(self) -> (OwnedReadHalf, OwnedWriteHalf) {
+        split_owned(self)
+    }
+
+    // == Poll IO functions that takes `&self` ==
+    //
+    // To read or write without mutable access to the `UnixStream`, combine the
+    // `poll_read_ready` or `poll_write_ready` methods with the `try_read` or
+    // `try_write` methods.
+
+    pub(crate) fn poll_read_priv(
+        &self,
+        cx: &mut Context<'_>,
+        buf: &mut ReadBuf<'_>,
+    ) -> Poll<io::Result<()>> {
+        // Safety: `TcpStream::read` correctly handles reads into uninitialized memory
+        unsafe { self.io.poll_read(cx, buf) }
+    }
+
+    pub(super) fn poll_write_priv(
+        &self,
+        cx: &mut Context<'_>,
+        buf: &[u8],
+    ) -> Poll<io::Result<usize>> {
+        self.io.poll_write(cx, buf)
+    }
+
+    pub(super) fn poll_write_vectored_priv(
+        &self,
+        cx: &mut Context<'_>,
+        bufs: &[io::IoSlice<'_>],
+    ) -> Poll<io::Result<usize>> {
+        self.io.poll_write_vectored(cx, bufs)
+    }
+}
+
+impl TryFrom<std::net::TcpStream> for TcpStream {
+    type Error = io::Error;
+
+    /// Consumes stream, returning the tokio I/O object.
+    ///
+    /// This is equivalent to
+    /// [`TcpStream::from_std(stream)`](TcpStream::from_std).
+    fn try_from(stream: std::net::TcpStream) -> Result<Self, Self::Error> {
+        Self::from_std(stream)
+    }
+}
+
+// ===== impl Read / Write =====
+
+impl AsyncRead for TcpStream {
+    fn poll_read(
+        self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+        buf: &mut ReadBuf<'_>,
+    ) -> Poll<io::Result<()>> {
+        self.poll_read_priv(cx, buf)
+    }
+}
+
+impl AsyncWrite for TcpStream {
+    fn poll_write(
+        self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+        buf: &[u8],
+    ) -> Poll<io::Result<usize>> {
+        self.poll_write_priv(cx, buf)
+    }
+
+    fn poll_write_vectored(
+        self: Pin<&mut Self>,
+        cx: &mut Context<'_>,
+        bufs: &[io::IoSlice<'_>],
+    ) -> Poll<io::Result<usize>> {
+        self.poll_write_vectored_priv(cx, bufs)
+    }
+
+    fn is_write_vectored(&self) -> bool {
+        true
+    }
+
+    #[inline]
+    fn poll_flush(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<()>> {
+        // tcp flush is a no-op
+        Poll::Ready(Ok(()))
+    }
+
+    fn poll_shutdown(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<io::Result<()>> {
+        self.shutdown_std(std::net::Shutdown::Write)?;
+        Poll::Ready(Ok(()))
+    }
+}
+
+impl fmt::Debug for TcpStream {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        self.io.fmt(f)
+    }
+}
+
+#[cfg(unix)]
+mod sys {
+    use super::TcpStream;
+    use std::os::unix::prelude::*;
+
+    impl AsRawFd for TcpStream {
+        fn as_raw_fd(&self) -> RawFd {
+            self.io.as_raw_fd()
+        }
+    }
+}
+
+#[cfg(windows)]
+mod sys {
+    use super::TcpStream;
+    use std::os::windows::prelude::*;
+
+    impl AsRawSocket for TcpStream {
+        fn as_raw_socket(&self) -> RawSocket {
+            self.io.as_raw_socket()
+        }
+    }
+}