1 files changed, 46 insertions, 0 deletions
diff --git a/tokio/src/io/util/write.rs b/tokio/src/io/util/write.rs
new file mode 100644
index 00000000..42e59848
--- /dev/null
+++ b/tokio/src/io/util/write.rs
@@ -0,0 +1,46 @@
+use crate::io::AsyncWrite;
+
+use std::future::Future;
+use std::io;
+use std::pin::Pin;
+use std::task::{Context, Poll};
+
+/// A future to write some of the buffer to an `AsyncWrite`.
+#[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
+pub struct Write<'a, W: ?Sized> {
+    writer: &'a mut W,
+    buf: &'a [u8],
+}
+
+/// Tries to write some bytes from the given `buf` to the writer in an
+/// asynchronous manner, returning a future.
+pub(crate) fn write<'a, W>(writer: &'a mut W, buf: &'a [u8]) -> Write<'a, W>
+where
+    W: AsyncWrite + Unpin + ?Sized,
+{
+    Write { writer, buf }
+}
+
+impl<W> Future for Write<'_, W>
+where
+    W: AsyncWrite + Unpin + ?Sized,
+{
+    type Output = io::Result<usize>;
+
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<io::Result<usize>> {
+        let me = &mut *self;
+        Pin::new(&mut *me.writer).poll_write(cx, me.buf)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn assert_unpin() {
+        use std::marker::PhantomPinned;
+        crate::is_unpin::<Write<'_, PhantomPinned>>();
+    }
+}