Trait kvarn::websocket::Stream

pub trait Stream {
    type Item;

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

    // Provided method
    fn size_hint(&self) -> (usize, Option<usize>) { ... }
}

Available on crate feature websocket only.

A stream of values produced asynchronously.

If Future<Output = T> is an asynchronous version of T, then Stream<Item = T> is an asynchronous version of Iterator<Item = T>. A stream represents a sequence of value-producing events that occur asynchronously to the caller.

The trait is modeled after Future, but allows poll_next to be called even after a value has been produced, yielding None once the stream has been fully exhausted.

Required Associated Types

type Item

Values yielded by the stream.

Required Methods

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.

Return value

There are several possible return values, each indicating a distinct stream state:

• Poll::Pending means that this stream’s next value is not ready yet. Implementations will ensure that the current task will be notified when the next value may be ready.

• Poll::Ready(Some(val)) means that the stream has successfully produced a value, val, and may produce further values on subsequent poll_next calls.

• Poll::Ready(None) means that the stream has terminated, and poll_next should not be invoked again.

Panics

Once a stream has finished (returned Ready(None) from poll_next), calling its poll_next method again may panic, block forever, or cause other kinds of problems; the Stream trait places no requirements on the effects of such a call. However, as the poll_next method is not marked unsafe, Rust’s usual rules apply: calls must never cause undefined behavior (memory corruption, incorrect use of unsafe functions, or the like), regardless of the stream’s state.

If this is difficult to guard against then the fuse adapter can be used to ensure that poll_next always returns Ready(None) in subsequent calls.

Provided Methods

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

Returns the bounds on the remaining length of the stream.

Specifically, size_hint() returns a tuple where the first element is the lower bound, and the second element is the upper bound.

The second half of the tuple that is returned is an Option<usize>. A None here means that either there is no known upper bound, or the upper bound is larger than usize.

Implementation notes

It is not enforced that a stream implementation yields the declared number of elements. A buggy stream may yield less than the lower bound or more than the upper bound of elements.

size_hint() is primarily intended to be used for optimizations such as reserving space for the elements of the stream, but must not be trusted to e.g., omit bounds checks in unsafe code. An incorrect implementation of size_hint() should not lead to memory safety violations.

That said, the implementation should provide a correct estimation, because otherwise it would be a violation of the trait’s protocol.

The default implementation returns (0, None) which is correct for any stream.

Implementations on Foreign Types

impl<St> Stream for Enumerate<St>where St: Stream,

type Item = (usize, <St as Stream>::Item)

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

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

impl<St> Stream for SelectAll<St>where St: Stream + Unpin,

type Item = <St as Stream>::Item

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

impl<St, Fut, F, T> Stream for FilterMap<St, Fut, F>where St: Stream, F: FnMut1<<St as Stream>::Item, Output = Fut>, Fut: Future<Output = Option<T>>,

type Item = T

fn poll_next( self: Pin<&mut FilterMap<St, Fut, F>>, cx: &mut Context<'_> ) -> Poll<Option<T>>

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

impl<St, U, F> Stream for FlatMapUnordered<St, U, F>where FlattenUnorderedWithFlowController<Map<St, F>, ()>: Stream, St: Stream, U: Stream + Unpin, F: FnMut(<St as Stream>::Item) -> U,

type Item = <FlattenUnorderedWithFlowController<Map<St, F>, ()> as Stream>::Item

fn poll_next( self: Pin<&mut FlatMapUnordered<St, U, F>>, cx: &mut Context<'_> ) -> Poll<Option<<FlatMapUnordered<St, U, F> as Stream>::Item>>

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

impl<St, Fut, F, T> Stream for TryFilterMap<St, Fut, F>where St: TryStream, Fut: TryFuture<Ok = Option<T>, Error = <St as TryStream>::Error>, F: FnMut(<St as TryStream>::Ok) -> Fut,

type Item = Result<T, <St as TryStream>::Error>

fn poll_next( self: Pin<&mut TryFilterMap<St, Fut, F>>, cx: &mut Context<'_> ) -> Poll<Option<<TryFilterMap<St, Fut, F> as Stream>::Item>>

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

impl<St, Fut, F> Stream for AndThen<St, Fut, F>where St: TryStream, F: FnMut(<St as TryStream>::Ok) -> Fut, Fut: TryFuture<Error = <St as TryStream>::Error>,

type Item = Result<<Fut as TryFuture>::Ok, <St as TryStream>::Error>

fn poll_next( self: Pin<&mut AndThen<St, Fut, F>>, cx: &mut Context<'_> ) -> Poll<Option<<AndThen<St, Fut, F> as Stream>::Item>>

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

impl<B, St, S, Fut, F> Stream for Scan<St, S, Fut, F>where St: Stream, F: FnMut(&mut S, <St as Stream>::Item) -> Fut, Fut: Future<Output = Option<B>>,

type Item = B

fn poll_next( self: Pin<&mut Scan<St, S, Fut, F>>, cx: &mut Context<'_> ) -> Poll<Option<B>>

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

impl<Fut> Stream for TryFlattenStream<Fut>where TryFlatten<Fut, <Fut as TryFuture>::Ok>: Stream, Fut: TryFuture,

type Item = <TryFlatten<Fut, <Fut as TryFuture>::Ok> as Stream>::Item

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

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

impl<St, Fut, F> Stream for TryTakeWhile<St, Fut, F>where St: TryStream, F: FnMut(&<St as TryStream>::Ok) -> Fut, Fut: TryFuture<Ok = bool, Error = <St as TryStream>::Error>,

type Item = Result<<St as TryStream>::Ok, <St as TryStream>::Error>

fn poll_next( self: Pin<&mut TryTakeWhile<St, Fut, F>>, cx: &mut Context<'_> ) -> Poll<Option<<TryTakeWhile<St, Fut, F> as Stream>::Item>>

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

impl<S, Item, U, Fut, F> Stream for With<S, Item, U, Fut, F>where S: Stream + Sink<Item>, F: FnMut(U) -> Fut, Fut: Future,

type Item = <S as Stream>::Item

fn poll_next( self: Pin<&mut With<S, Item, U, Fut, F>>, cx: &mut Context<'_> ) -> Poll<Option<<With<S, Item, U, Fut, F> as Stream>::Item>>

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

impl<St1, St2> Stream for Select<St1, St2>where St1: Stream, St2: Stream<Item = <St1 as Stream>::Item>,

type Item = <St1 as Stream>::Item

fn poll_next( self: Pin<&mut Select<St1, St2>>, cx: &mut Context<'_> ) -> Poll<Option<<St1 as Stream>::Item>>

impl<S> Stream for Fuse<S>where S: Stream,

type Item = <S as Stream>::Item

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

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

impl<St> Stream for Buffered<St>where St: Stream, <St as Stream>::Item: Future,

type Item = <<St as Stream>::Item as Future>::Output

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

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

impl<F> Stream for IntoStream<F>where Once<F>: Stream,

type Item = <Once<F> as Stream>::Item

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

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

impl<Fut, Si> Stream for FlattenSink<Fut, Si>where TryFlatten<Fut, Si>: Stream,

type Item = <TryFlatten<Fut, Si> as Stream>::Item

fn poll_next( self: Pin<&mut FlattenSink<Fut, Si>>, cx: &mut Context<'_> ) -> Poll<Option<<FlattenSink<Fut, Si> as Stream>::Item>>

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

impl<S> Stream for SplitStream<S>where S: Stream,

type Item = <S as Stream>::Item

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

impl<Fut> Stream for FuturesOrdered<Fut>where Fut: Future,

type Item = <Fut as Future>::Output

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

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

impl<St> Stream for Skip<St>where St: Stream,

type Item = <St as Stream>::Item

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

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

impl<St, F> Stream for Map<St, F>where St: Stream, F: FnMut1<<St as Stream>::Item>,

type Item = <F as FnOnce1<<St as Stream>::Item>>::Output

fn poll_next( self: Pin<&mut Map<St, F>>, cx: &mut Context<'_> ) -> Poll<Option<<Map<St, F> as Stream>::Item>>

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

impl<S> Stream for Peekable<S>where S: Stream,

type Item = <S as Stream>::Item

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

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

impl<St> Stream for Cycle<St>where St: Clone + Stream,

type Item = <St as Stream>::Item

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

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

impl<St, Fut, F> Stream for TrySkipWhile<St, Fut, F>where St: TryStream, F: FnMut(&<St as TryStream>::Ok) -> Fut, Fut: TryFuture<Ok = bool, Error = <St as TryStream>::Error>,

type Item = Result<<St as TryStream>::Ok, <St as TryStream>::Error>

fn poll_next( self: Pin<&mut TrySkipWhile<St, Fut, F>>, cx: &mut Context<'_> ) -> Poll<Option<<TrySkipWhile<St, Fut, F> as Stream>::Item>>

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

impl<St> Stream for ReadyChunks<St>where St: Stream,

type Item = Vec<<St as Stream>::Item, Global>

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

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

impl<St, Fut, F> Stream for TakeWhile<St, Fut, F>where St: Stream, F: FnMut(&<St as Stream>::Item) -> Fut, Fut: Future<Output = bool>,

type Item = <St as Stream>::Item

fn poll_next( self: Pin<&mut TakeWhile<St, Fut, F>>, cx: &mut Context<'_> ) -> Poll<Option<<St as Stream>::Item>>

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

impl<St> Stream for BufferUnordered<St>where St: Stream, <St as Stream>::Item: Future,

type Item = <<St as Stream>::Item as Future>::Output

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

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

impl<St, Fut, F> Stream for Filter<St, Fut, F>where St: Stream, F: for<'a> FnMut1<&'a <St as Stream>::Item, Output = Fut>, Fut: Future<Output = bool>,

type Item = <St as Stream>::Item

fn poll_next( self: Pin<&mut Filter<St, Fut, F>>, cx: &mut Context<'_> ) -> Poll<Option<<St as Stream>::Item>>

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

impl<T> Stream for Empty<T>

type Item = T

fn poll_next( self: Pin<&mut Empty<T>>, _: &mut Context<'_> ) -> Poll<Option<<Empty<T> as Stream>::Item>>

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

impl<A, B> Stream for Either<A, B>where A: Stream, B: Stream<Item = <A as Stream>::Item>,

type Item = <A as Stream>::Item

fn poll_next( self: Pin<&mut Either<A, B>>, cx: &mut Context<'_> ) -> Poll<Option<<Either<A, B> as Stream>::Item>>

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

impl<St> Stream for TryChunks<St>where St: TryStream,

type Item = Result<Vec<<St as TryStream>::Ok, Global>, TryChunksError<<St as TryStream>::Ok, <St as TryStream>::Error>>

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

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

impl<I> Stream for Iter<I>where I: Iterator,

type Item = <I as Iterator>::Item

fn poll_next( self: Pin<&mut Iter<I>>, _: &mut Context<'_> ) -> Poll<Option<<I as Iterator>::Item>>

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

impl<Fut> Stream for FuturesUnordered<Fut>where Fut: Future,

type Item = <Fut as Future>::Output

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

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

impl<R> Stream for Lines<R>where R: AsyncBufRead,

type Item = Result<String, Error>

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

impl<St, U, F> Stream for FlatMap<St, U, F>where Flatten<Map<St, F>, U>: Stream,

type Item = <Flatten<Map<St, F>, U> as Stream>::Item

fn poll_next( self: Pin<&mut FlatMap<St, U, F>>, cx: &mut Context<'_> ) -> Poll<Option<<FlatMap<St, U, F> as Stream>::Item>>

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

impl<St> Stream for TryFlattenUnordered<St>where FlattenUnorderedWithFlowController<NestedTryStreamIntoEitherTryStream<St>, PropagateBaseStreamError<St>>: Stream, St: TryStream, <St as TryStream>::Ok: TryStream + Unpin, <<St as TryStream>::Ok as TryStream>::Error: From<<St as TryStream>::Error>,

type Item = <FlattenUnorderedWithFlowController<NestedTryStreamIntoEitherTryStream<St>, PropagateBaseStreamError<St>> as Stream>::Item

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

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

impl<St> Stream for Abortable<St>where St: Stream,

type Item = <St as Stream>::Item

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

impl<St> Stream for CatchUnwind<St>where St: Stream + UnwindSafe,

type Item = Result<<St as Stream>::Item, Box<dyn Any + Send + 'static, Global>>

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

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

impl<T, S> Stream for PollImmediate<S>where S: Stream<Item = T>,

type Item = Poll<T>

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

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

impl<St1, St2, Clos, State> Stream for SelectWithStrategy<St1, St2, Clos, State>where St1: Stream, St2: Stream<Item = <St1 as Stream>::Item>, Clos: FnMut(&mut State) -> PollNext,

type Item = <St1 as Stream>::Item

fn poll_next( self: Pin<&mut SelectWithStrategy<St1, St2, Clos, State>>, cx: &mut Context<'_> ) -> Poll<Option<<St1 as Stream>::Item>>

impl<St, F> Stream for MapErr<St, F>where Map<IntoStream<St>, MapErrFn<F>>: Stream,

type Item = <Map<IntoStream<St>, MapErrFn<F>> as Stream>::Item

fn poll_next( self: Pin<&mut MapErr<St, F>>, cx: &mut Context<'_> ) -> Poll<Option<<MapErr<St, F> as Stream>::Item>>

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

impl<S, Item, E> Stream for SinkErrInto<S, Item, E>where S: Sink<Item> + Stream, <S as Sink<Item>>::Error: Into<E>,

type Item = <S as Stream>::Item

fn poll_next( self: Pin<&mut SinkErrInto<S, Item, E>>, cx: &mut Context<'_> ) -> Poll<Option<<SinkErrInto<S, Item, E> as Stream>::Item>>

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

impl<St> Stream for TryBuffered<St>where St: TryStream, <St as TryStream>::Ok: TryFuture<Error = <St as TryStream>::Error>,

type Item = Result<<<St as TryStream>::Ok as TryFuture>::Ok, <St as TryStream>::Error>

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

impl<St, Fut, F> Stream for TryFilter<St, Fut, F>where St: TryStream, Fut: Future<Output = bool>, F: FnMut(&<St as TryStream>::Ok) -> Fut,

type Item = Result<<St as TryStream>::Ok, <St as TryStream>::Error>

fn poll_next( self: Pin<&mut TryFilter<St, Fut, F>>, cx: &mut Context<'_> ) -> Poll<Option<<TryFilter<St, Fut, F> as Stream>::Item>>

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

impl<St, E> Stream for ErrInto<St, E>where MapErr<St, IntoFn<E>>: Stream,

type Item = <MapErr<St, IntoFn<E>> as Stream>::Item

fn poll_next( self: Pin<&mut ErrInto<St, E>>, cx: &mut Context<'_> ) -> Poll<Option<<ErrInto<St, E> as Stream>::Item>>

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

impl<St, Fut, F> Stream for SkipWhile<St, Fut, F>where St: Stream, F: FnMut(&<St as Stream>::Item) -> Fut, Fut: Future<Output = bool>,

type Item = <St as Stream>::Item

fn poll_next( self: Pin<&mut SkipWhile<St, Fut, F>>, cx: &mut Context<'_> ) -> Poll<Option<<St as Stream>::Item>>

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

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

type Item = <Fut as Future>::Output

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

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

impl<St1, St2> Stream for Chain<St1, St2>where St1: Stream, St2: Stream<Item = <St1 as Stream>::Item>,

type Item = <St1 as Stream>::Item

fn poll_next( self: Pin<&mut Chain<St1, St2>>, cx: &mut Context<'_> ) -> Poll<Option<<Chain<St1, St2> as Stream>::Item>>

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

impl<St, Fut> Stream for TakeUntil<St, Fut>where St: Stream, Fut: Future,

type Item = <St as Stream>::Item

fn poll_next( self: Pin<&mut TakeUntil<St, Fut>>, cx: &mut Context<'_> ) -> Poll<Option<<St as Stream>::Item>>

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

impl<T, F> Stream for PollFn<F>where F: FnMut(&mut Context<'_>) -> Poll<Option<T>>,

type Item = T

fn poll_next(self: Pin<&mut PollFn<F>>, cx: &mut Context<'_>) -> Poll<Option<T>>

impl<St> Stream for Chunks<St>where St: Stream,

type Item = Vec<<St as Stream>::Item, Global>

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

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

impl<T, F, Fut, Item> Stream for TryUnfold<T, F, Fut>where F: FnMut(T) -> Fut, Fut: TryFuture<Ok = Option<(Item, T)>>,

type Item = Result<Item, <Fut as TryFuture>::Error>

fn poll_next( self: Pin<&mut TryUnfold<T, F, Fut>>, cx: &mut Context<'_> ) -> Poll<Option<<TryUnfold<T, F, Fut> as Stream>::Item>>

impl<St1, St2> Stream for Zip<St1, St2>where St1: Stream, St2: Stream,

type Item = (<St1 as Stream>::Item, <St2 as Stream>::Item)

fn poll_next( self: Pin<&mut Zip<St1, St2>>, cx: &mut Context<'_> ) -> Poll<Option<<Zip<St1, St2> as Stream>::Item>>

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

impl<St, F> Stream for MapOk<St, F>where Map<IntoStream<St>, MapOkFn<F>>: Stream,

type Item = <Map<IntoStream<St>, MapOkFn<F>> as Stream>::Item

fn poll_next( self: Pin<&mut MapOk<St, F>>, cx: &mut Context<'_> ) -> Poll<Option<<MapOk<St, F> as Stream>::Item>>

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

impl<St> Stream for TryFlatten<St>where St: TryStream, <St as TryStream>::Ok: TryStream, <<St as TryStream>::Ok as TryStream>::Error: From<<St as TryStream>::Error>,

type Item = Result<<<St as TryStream>::Ok as TryStream>::Ok, <<St as TryStream>::Ok as TryStream>::Error>

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

impl<St, Fut, F> Stream for OrElse<St, Fut, F>where St: TryStream, F: FnMut(<St as TryStream>::Error) -> Fut, Fut: TryFuture<Ok = <St as TryStream>::Ok>,

type Item = Result<<St as TryStream>::Ok, <Fut as TryFuture>::Error>

fn poll_next( self: Pin<&mut OrElse<St, Fut, F>>, cx: &mut Context<'_> ) -> Poll<Option<<OrElse<St, Fut, F> as Stream>::Item>>

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

impl<St, F> Stream for InspectOk<St, F>where Inspect<IntoStream<St>, InspectOkFn<F>>: Stream,

type Item = <Inspect<IntoStream<St>, InspectOkFn<F>> as Stream>::Item

fn poll_next( self: Pin<&mut InspectOk<St, F>>, cx: &mut Context<'_> ) -> Poll<Option<<InspectOk<St, F> as Stream>::Item>>

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

impl<St, F> Stream for InspectErr<St, F>where Inspect<IntoStream<St>, InspectErrFn<F>>: Stream,

type Item = <Inspect<IntoStream<St>, InspectErrFn<F>> as Stream>::Item

fn poll_next( self: Pin<&mut InspectErr<St, F>>, cx: &mut Context<'_> ) -> Poll<Option<<InspectErr<St, F> as Stream>::Item>>

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

impl<St, F> Stream for Inspect<St, F>where Map<St, InspectFn<F>>: Stream,

type Item = <Map<St, InspectFn<F>> as Stream>::Item

fn poll_next( self: Pin<&mut Inspect<St, F>>, cx: &mut Context<'_> ) -> Poll<Option<<Inspect<St, F> as Stream>::Item>>

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

impl<St> Stream for TryBufferUnordered<St>where St: TryStream, <St as TryStream>::Ok: TryFuture<Error = <St as TryStream>::Error>,

type Item = Result<<<St as TryStream>::Ok as TryFuture>::Ok, <St as TryStream>::Error>

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

impl<S, Item> Stream for Buffer<S, Item>where S: Sink<Item> + Stream,

type Item = <S as Stream>::Item

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

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

impl<St> Stream for Take<St>where St: Stream,

type Item = <St as Stream>::Item

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

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

impl<S, F> Stream for SinkMapErr<S, F>where S: Stream,

type Item = <S as Stream>::Item

fn poll_next( self: Pin<&mut SinkMapErr<S, F>>, cx: &mut Context<'_> ) -> Poll<Option<<SinkMapErr<S, F> as Stream>::Item>>

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

impl<S, Item, U, St, F> Stream for WithFlatMap<S, Item, U, St, F>where S: Stream + Sink<Item>, F: FnMut(U) -> St, St: Stream<Item = Result<Item, <S as Sink<Item>>::Error>>,

type Item = <S as Stream>::Item

fn poll_next( self: Pin<&mut WithFlatMap<S, Item, U, St, F>>, cx: &mut Context<'_> ) -> Poll<Option<<WithFlatMap<S, Item, U, St, F> as Stream>::Item>>

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

impl<St> Stream for IntoStream<St>where St: TryStream,

type Item = Result<<St as TryStream>::Ok, <St as TryStream>::Error>

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

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

impl<T> Stream for Pending<T>

type Item = T

fn poll_next( self: Pin<&mut Pending<T>>, _: &mut Context<'_> ) -> Poll<Option<<Pending<T> as Stream>::Item>>

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

impl<St> Stream for Flatten<St>where Flatten<St, <St as Stream>::Item>: Stream, St: Stream,

type Item = <Flatten<St, <St as Stream>::Item> as Stream>::Item

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

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

impl<F> Stream for FlattenStream<F>where Flatten<F, <F as Future>::Output>: Stream, F: Future,

type Item = <Flatten<F, <F as Future>::Output> as Stream>::Item

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

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

impl<T, F> Stream for PollImmediate<F>where F: Future<Output = T>,

A Stream implementation that can be polled repeatedly until the future is done. The stream will never return Poll::Pending so polling it in a tight loop is worse than using a blocking synchronous function.

use futures::task::Poll;
use futures::{StreamExt, future, pin_mut};
use future::FusedFuture;

let f = async { 1_u32 };
pin_mut!(f);
let mut r = future::poll_immediate(f);
assert_eq!(r.next().await, Some(Poll::Ready(1)));

let f = async {futures::pending!(); 42_u8};
pin_mut!(f);
let mut p = future::poll_immediate(f);
assert_eq!(p.next().await, Some(Poll::Pending));
assert!(!p.is_terminated());
assert_eq!(p.next().await, Some(Poll::Ready(42)));
assert!(p.is_terminated());
assert_eq!(p.next().await, None);

type Item = Poll<T>

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

impl<T> Stream for Repeat<T>where T: Clone,

type Item = T

fn poll_next( self: Pin<&mut Repeat<T>>, _: &mut Context<'_> ) -> Poll<Option<<Repeat<T> as Stream>::Item>>

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

impl<A, F> Stream for RepeatWith<F>where F: FnMut() -> A,

type Item = A

fn poll_next( self: Pin<&mut RepeatWith<F>>, _: &mut Context<'_> ) -> Poll<Option<<RepeatWith<F> as Stream>::Item>>

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

impl<St, Fut, F> Stream for Then<St, Fut, F>where St: Stream, F: FnMut(<St as Stream>::Item) -> Fut, Fut: Future,

type Item = <Fut as Future>::Output

fn poll_next( self: Pin<&mut Then<St, Fut, F>>, cx: &mut Context<'_> ) -> Poll<Option<<Then<St, Fut, F> as Stream>::Item>>

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

impl<T, F, Fut, Item> Stream for Unfold<T, F, Fut>where F: FnMut(T) -> Fut, Fut: Future<Output = Option<(Item, T)>>,

type Item = Item

fn poll_next( self: Pin<&mut Unfold<T, F, Fut>>, cx: &mut Context<'_> ) -> Poll<Option<<Unfold<T, F, Fut> as Stream>::Item>>

impl<S> Stream for &mut Swhere S: Stream + Unpin + ?Sized,

type Item = <S as Stream>::Item

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

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

impl<S> Stream for Box<S, Global>where S: Stream + Unpin + ?Sized,

type Item = <S as Stream>::Item

fn poll_next( self: Pin<&mut Box<S, Global>>, cx: &mut Context<'_> ) -> Poll<Option<<Box<S, Global> as Stream>::Item>>

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

impl<T> Stream for Receiver<T>

type Item = T

fn poll_next( self: Pin<&mut Receiver<T>>, cx: &mut Context<'_> ) -> Poll<Option<T>>

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

impl<T> Stream for UnboundedReceiver<T>

type Item = T

fn poll_next( self: Pin<&mut UnboundedReceiver<T>>, cx: &mut Context<'_> ) -> Poll<Option<T>>

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

impl<T> Stream for WebSocketStream<T>where T: AsyncRead + AsyncWrite + Unpin,

type Item = Result<Message, Error>

fn poll_next( self: Pin<&mut WebSocketStream<T>>, cx: &mut Context<'_> ) -> Poll<Option<<WebSocketStream<T> as Stream>::Item>>

impl Stream for PollSemaphore

type Item = OwnedSemaphorePermit

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

impl<T, U> Stream for Framed<T, U>where T: AsyncRead, U: Decoder,

type Item = Result<<U as Decoder>::Item, <U as Decoder>::Error>

fn poll_next( self: Pin<&mut Framed<T, U>>, cx: &mut Context<'_> ) -> Poll<Option<<Framed<T, U> as Stream>::Item>>

impl<T, D> Stream for FramedRead<T, D>where T: AsyncRead, D: Decoder,

type Item = Result<<D as Decoder>::Item, <D as Decoder>::Error>

fn poll_next( self: Pin<&mut FramedRead<T, D>>, cx: &mut Context<'_> ) -> Poll<Option<<FramedRead<T, D> as Stream>::Item>>

impl<L, R> Stream for Either<L, R>where L: Stream, R: Stream<Item = <L as Stream>::Item>,

type Item = <L as Stream>::Item

fn poll_next( self: Pin<&mut Either<L, R>>, cx: &mut Context<'_> ) -> Poll<Option<<Either<L, R> as Stream>::Item>>

impl<T, D> Stream for FramedWrite<T, D>where T: Stream,

type Item = <T as Stream>::Item

fn poll_next( self: Pin<&mut FramedWrite<T, D>>, cx: &mut Context<'_> ) -> Poll<Option<<FramedWrite<T, D> as Stream>::Item>>

Implementors

impl<P> Stream for Pin<P>where P: DerefMut + Unpin, <P as Deref>::Target: Stream,

type Item = <<P as Deref>::Target as Stream>::Item

impl<S> Stream for AssertUnwindSafe<S>where S: Stream,

Available on crate feature std only.

type Item = <S as Stream>::Item