1 files changed, 41 insertions, 0 deletions
diff --git a/third_party/rust/futures-util/src/sink/send.rs b/third_party/rust/futures-util/src/sink/send.rs
new file mode 100644
index 0000000000..6d21f33fe4
--- /dev/null
+++ b/third_party/rust/futures-util/src/sink/send.rs
@@ -0,0 +1,41 @@
+use super::Feed;
+use core::pin::Pin;
+use futures_core::future::Future;
+use futures_core::ready;
+use futures_core::task::{Context, Poll};
+use futures_sink::Sink;
+
+/// Future for the [`send`](super::SinkExt::send) method.
+#[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
+pub struct Send<'a, Si: ?Sized, Item> {
+    feed: Feed<'a, Si, Item>,
+}
+
+// Pinning is never projected to children
+impl<Si: Unpin + ?Sized, Item> Unpin for Send<'_, Si, Item> {}
+
+impl<'a, Si: Sink<Item> + Unpin + ?Sized, Item> Send<'a, Si, Item> {
+    pub(super) fn new(sink: &'a mut Si, item: Item) -> Self {
+        Self { feed: Feed::new(sink, item) }
+    }
+}
+
+impl<Si: Sink<Item> + Unpin + ?Sized, Item> Future for Send<'_, Si, Item> {
+    type Output = Result<(), Si::Error>;
+
+    fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        let this = &mut *self;
+
+        if this.feed.is_item_pending() {
+            ready!(Pin::new(&mut this.feed).poll(cx))?;
+            debug_assert!(!this.feed.is_item_pending());
+        }
+
+        // we're done sending the item, but want to block on flushing the
+        // sink
+        ready!(this.feed.sink_pin_mut().poll_flush(cx))?;
+
+        Poll::Ready(Ok(()))
+    }
+}