Struct ParallelBuffered 

pub struct ParallelBuffered<St>(/* private fields */)
where
    St: Stream,
    St::Item: Future + Send + 'static,
    <St::Item as Future>::Output: Send;

Given a Stream where every item is a Future, this stream buffers up to a certain number of futures, runs them in parallel on separate tasks, and returns the results of the futures in the order in which they appeared in the input stream.

If any of the futures panics, all other futures and tasks are immediately cancelled and the panic gets returned immediately.

This stream is cancellation safe if the inner stream and generated futures are also cancellation safe. This means that dropping this stream will also cancel any outstanding tasks and drop the relevant futures/streams.

You can use ParallelBuffered::awaiting_completion to control whether we wait for all tasks to fully terminate before this stream is considered to have ended.

Implementations

impl<St> ParallelBuffered<St>

where St: Stream, St::Item: Future + Send + 'static, <St::Item as Future>::Output: Send,

pub fn awaiting_completion(self, value: bool) -> Self

Whether to always await completion for the tasks from the StreamParExt::parallel_buffered or StreamParExt::parallel_buffered_with_token call, even when one of the futures has panicked or been cancelled.

Trait Implementations

impl<St> Debug for ParallelBuffered<St>

where St: Debug + Stream, St::Item: Debug + Future + Send, <St::Item as Future>::Output: Send,

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

Formats the value using the given formatter.

impl<St> Stream for ParallelBuffered<St>

where St: Stream, St::Item: Future + Send, <St::Item as Future>::Output: Send,

type Item = <<St as Stream>::Item as Future>::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, St> Unpin for ParallelBuffered<St>

where St: Stream, St::Item: Future + Send + 'static, <St::Item as Future>::Output: Send, PinnedFieldsOf<__ParallelBuffered<'pin, St>>: Unpin,