Struct futures_util::stream::Once

#[must_use = "streams do nothing unless polled"]pub struct Once<Fut> { /* fields omitted */ }

A stream which emits single element and then EOF.

This stream will never block and is always ready.

Trait Implementations

impl<Fut: Debug> Debug for Once<Fut>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<Fut: Future> FusedStream for Once<Fut>

fn is_terminated(&self) -> bool

Returns true if the stream should no longer be polled.

impl<Fut> PinnedDrop for Once<Fut>

unsafe fn drop(self: Pin<&mut Self>)

impl<Fut: Future> Stream for Once<Fut>

type Item = Fut::Output

Values yielded by the stream.

fn poll_next(
    self: Pin<&mut Self>,
    cx: &mut Context<'_>
) -> Poll<Option<Self::Item>>

Attempt to pull out the next value of this stream, registering the current task for wakeup if the value is not yet available, and returning None if the stream is exhausted.

fn size_hint(&self) -> (usize, Option<usize>)

Returns the bounds on the remaining length of the stream.

impl<'pin, Fut> Unpin for Once<Fut> where
    __Once<'pin, Fut>: Unpin, 

impl<Fut> UnsafeUnpin for Once<Fut>