1use futures_core::future::Future;
2use futures_core::task::{Context, Poll};
3use futures_io::AsyncWrite;
4use std::io;
5use std::pin::Pin;
6
7/// Future for the [`flush`](super::AsyncWriteExt::flush) method.
8#[derive(Debug)]
9#[must_use = "futures do nothing unless you `.await` or poll them"]
10pub struct Flush<'a, W: ?Sized> {
11 writer: &'a mut W,
12}
13
14impl<W: ?Sized + Unpin> Unpin for Flush<'_, W> {}
15
16impl<'a, W: AsyncWrite + ?Sized + Unpin> Flush<'a, W> {
17 pub(super) fn new(writer: &'a mut W) -> Self {
18 Self { writer }
19 }
20}
21
22impl<W> Future for Flush<'_, W>
23where
24 W: AsyncWrite + ?Sized + Unpin,
25{
26 type Output = io::Result<()>;
27
28 fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
29 Pin::new(&mut *self.writer).poll_flush(cx)
30 }
31}
32