1 use crate::stream::Stream;
2 
3 use core::future::Future;
4 use core::pin::Pin;
5 use core::task::{Context, Poll};
6 
7 /// Future for the [`next`](super::StreamExt::next) method.
8 #[derive(Debug)]
9 #[must_use = "futures do nothing unless you `.await` or poll them"]
10 pub struct Next<'a, St: ?Sized> {
11     stream: &'a mut St,
12 }
13 
14 impl<St: ?Sized + Unpin> Unpin for Next<'_, St> {}
15 
16 impl<'a, St: ?Sized> Next<'a, St> {
new(stream: &'a mut St) -> Self17     pub(super) fn new(stream: &'a mut St) -> Self {
18         Next { stream }
19     }
20 }
21 
22 impl<St: ?Sized + Stream + Unpin> Future for Next<'_, St> {
23     type Output = Option<St::Item>;
24 
poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output>25     fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
26         Pin::new(&mut self.stream).poll_next(cx)
27     }
28 }
29