diff --git a/embassy-net/src/tcp.rs b/embassy-net/src/tcp.rs index d46bd4dbf..b9e494fc4 100644 --- a/embassy-net/src/tcp.rs +++ b/embassy-net/src/tcp.rs @@ -254,10 +254,19 @@ impl<'d> TcpIo<'d> { .await } - #[allow(unused)] async fn flush(&mut self) -> Result<(), Error> { - poll_fn(move |_| { - Poll::Ready(Ok(())) // TODO: Is there a better implementation for this? + poll_fn(move |cx| { + self.with_mut(|s, _| { + // If there are outstanding send operations, register for wake up and wait + // smoltcp issues wake-ups when octets are dequeued from the send buffer + if s.send_queue() > 0 { + s.register_send_waker(cx.waker()); + Poll::Pending + // No outstanding sends, socket is flushed + } else { + Poll::Ready(Ok(())) + } + }) }) .await }