Vendor dependencies

Let's see how I like this workflow.

vendor/tokio/src/io/util/read_until.rs

@@ -0,0 +1,79 @@
+use crate::io::AsyncBufRead;
+
+use pin_project_lite::pin_project;
+use std::future::Future;
+use std::io;
+use std::marker::PhantomPinned;
+use std::mem;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+
+pin_project! {
+    /// Future for the [`read_until`](crate::io::AsyncBufReadExt::read_until) method.
+    /// The delimiter is included in the resulting vector.
+    #[derive(Debug)]
+    #[must_use = "futures do nothing unless you `.await` or poll them"]
+    pub struct ReadUntil<'a, R: ?Sized> {
+        reader: &'a mut R,
+        delimiter: u8,
+        buf: &'a mut Vec<u8>,
+        // The number of bytes appended to buf. This can be less than buf.len() if
+        // the buffer was not empty when the operation was started.
+        read: usize,
+        // Make this future `!Unpin` for compatibility with async trait methods.
+        #[pin]
+        _pin: PhantomPinned,
+    }
+}
+
+pub(crate) fn read_until<'a, R>(
+    reader: &'a mut R,
+    delimiter: u8,
+    buf: &'a mut Vec<u8>,
+) -> ReadUntil<'a, R>
+where
+    R: AsyncBufRead + ?Sized + Unpin,
+{
+    ReadUntil {
+        reader,
+        delimiter,
+        buf,
+        read: 0,
+        _pin: PhantomPinned,
+    }
+}
+
+pub(super) fn read_until_internal<R: AsyncBufRead + ?Sized>(
+    mut reader: Pin<&mut R>,
+    cx: &mut Context<'_>,
+    delimiter: u8,
+    buf: &mut Vec<u8>,
+    read: &mut usize,
+) -> Poll<io::Result<usize>> {
+    loop {
+        let (done, used) = {
+            let available = ready!(reader.as_mut().poll_fill_buf(cx))?;
+            if let Some(i) = memchr::memchr(delimiter, available) {
+                buf.extend_from_slice(&available[..=i]);
+                (true, i + 1)
+            } else {
+                buf.extend_from_slice(available);
+                (false, available.len())
+            }
+        };
+        reader.as_mut().consume(used);
+        *read += used;
+        if done || used == 0 {
+            return Poll::Ready(Ok(mem::replace(read, 0)));
+        }
+    }
+}
+
+impl<R: AsyncBufRead + ?Sized + Unpin> Future for ReadUntil<'_, R> {
+    type Output = io::Result<usize>;
+
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        let me = self.project();
+        read_until_internal(Pin::new(*me.reader), cx, *me.delimiter, me.buf, me.read)
+    }
+}