Trait futures::prelude::Future

[+] Show declaration

[+] Expand attributes
#[must_use = "futures do nothing unless polled"]
pub trait Future {
type Output;
    fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output>;
}

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

[−] Expand description

A future represents an asynchronous computation.

A future is a value that may not have finished computing yet. This kind of "asynchronous value" makes it possible for a thread to continue doing useful work while it waits for the value to become available.

The poll method

The core method of future, poll, attempts to resolve the future into a final value. This method does not block if the value is not ready. Instead, the current task is scheduled to be woken up when it's possible to make further progress by polling again. The wake up is performed using the waker argument of the poll() method, which is a handle for waking up the current task.

When using a future, you generally won't call poll directly, but instead await! the value.

Associated Types

type Output[+]

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

The type of value produced on completion.

Required methods

fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output>[+]

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

Attempt to resolve the future to a final value, registering the current task for wakeup if the value is not yet available.

Return value

This function returns:

• Poll::Pending if the future is not ready yet
• Poll::Ready(val) with the result val of this future if it finished successfully.

Once a future has finished, clients should not poll it again.

When a future is not ready yet, poll returns Poll::Pending and stores a clone of the Waker copied from the current Context. This Waker is then woken once the future can make progress. For example, a future waiting for a socket to become readable would call .clone() on the Waker and store it. When a signal arrives elsewhere indicating that the socket is readable, [Waker::wake] is called and the socket future's task is awoken. Once a task has been woken up, it should attempt to poll the future again, which may or may not produce a final value.

Note that on multiple calls to poll, only the most recent Waker passed to poll should be scheduled to receive a wakeup.

Runtime characteristics

Futures alone are inert; they must be actively polled to make progress, meaning that each time the current task is woken up, it should actively re-poll pending futures that it still has an interest in.

The poll function is not called repeatedly in a tight loop -- instead, it should only be called when the future indicates that it is ready to make progress (by calling wake()). If you're familiar with the poll(2) or select(2) syscalls on Unix it's worth noting that futures typically do not suffer the same problems of "all wakeups must poll all events"; they are more like epoll(4).

An implementation of poll should strive to return quickly, and should not block. Returning quickly prevents unnecessarily clogging up threads or event loops. If it is known ahead of time that a call to poll may end up taking awhile, the work should be offloaded to a thread pool (or something similar) to ensure that poll can return quickly.

An implementation of poll may also never cause memory unsafety.

Panics

Once a future has completed (returned Ready from poll), then any future calls to poll may panic, block forever, or otherwise cause any kind of bad behavior except causing memory unsafety. The Future trait itself provides no guarantees about the behavior of poll after a future has completed.

Implementations on Foreign Types

impl<F> Future for AssertUnwindSafe<F> where
    F: Future, [−]

[+] Show hidden undocumented items

type Output = <F as Future>::Output

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut AssertUnwindSafe<F>>,
    cx: &mut Context
) -> Poll<<AssertUnwindSafe<F> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<P> Future for Pin<P> where
    P: Unpin + DerefMut,
    <P as Deref>::Target: Future, [−]

[+] Show hidden undocumented items

type Output = <<P as Deref>::Target as Future>::Output

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Pin<P>>,
    cx: &mut Context
) -> Poll<<Pin<P> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'_, F> Future for &'_ mut F where
    F: Unpin + Future + ?Sized, [−]

[+] Show hidden undocumented items

type Output = <F as Future>::Output

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut &'_ mut F>,
    cx: &mut Context
) -> Poll<<&'_ mut F as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<F> Future for Box<F> where
    F: Unpin + Future + ?Sized, [−]

[+] Show hidden undocumented items

type Output = <F as Future>::Output

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Box<F>>,
    cx: &mut Context
) -> Poll<<Box<F> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<St> Future for TryConcat<St> where
    St: TryStream,
    <St as TryStream>::Ok: Extend<<<St as TryStream>::Ok as IntoIterator>::Item>,
    <St as TryStream>::Ok: IntoIterator,
    <St as TryStream>::Ok: Default, [−]

[+] Show hidden undocumented items

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

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut TryConcat<St>>,
    cx: &mut Context
) -> Poll<<TryConcat<St> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'a, T> Future for BiLockAcquire<'a, T>[−]

[+] Show hidden undocumented items

type Output = BiLockGuard<'a, T>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut BiLockAcquire<'a, T>>,
    cx: &mut Context
) -> Poll<<BiLockAcquire<'a, T> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut, T> Future for UnitError<Fut> where
    Fut: Future<Output = T>, [−]

[+] Show hidden undocumented items

type Output = Result<T, ()>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(self: Pin<&mut UnitError<Fut>>, cx: &mut Context) -> Poll<Result<T, ()>>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

Implementors

impl<'_, A> Future for ReadToEnd<'_, A> where
    A: AsyncRead + Unpin + ?Sized, [−]

[+] Show hidden undocumented items

type Output = Result<(), Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut ReadToEnd<'_, A>>,
    cx: &mut Context
) -> Poll<<ReadToEnd<'_, A> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'_, R> Future for Read<'_, R> where
    R: Unpin + AsyncRead + ?Sized, [−]

[+] Show hidden undocumented items

type Output = Result<usize, Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Read<'_, R>>,
    cx: &mut Context
) -> Poll<<Read<'_, R> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'_, R> Future for ReadExact<'_, R> where
    R: Unpin + AsyncRead + ?Sized, [−]

[+] Show hidden undocumented items

type Output = Result<(), Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut ReadExact<'_, R>>,
    cx: &mut Context
) -> Poll<<ReadExact<'_, R> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'_, R, W> Future for CopyInto<'_, R, W> where
    R: AsyncRead + Unpin + ?Sized,
    W: AsyncWrite + Unpin + ?Sized, [−]

[+] Show hidden undocumented items

type Output = Result<u64, Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut CopyInto<'_, R, W>>,
    cx: &mut Context
) -> Poll<<CopyInto<'_, R, W> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'_, Si, Item> Future for futures::sink::Close<'_, Si, Item> where
    Si: Unpin + Sink<Item> + ?Sized, [−]

[+] Show hidden undocumented items

type Output = Result<(), <Si as Sink<Item>>::SinkError>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Close<'_, Si, Item>>,
    cx: &mut Context
) -> Poll<<Close<'_, Si, Item> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'_, Si, Item> Future for futures::sink::Flush<'_, Si, Item> where
    Si: Unpin + Sink<Item> + ?Sized, [−]

[+] Show hidden undocumented items

type Output = Result<(), <Si as Sink<Item>>::SinkError>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Flush<'_, Si, Item>>,
    cx: &mut Context
) -> Poll<<Flush<'_, Si, Item> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'_, Si, Item> Future for Send<'_, Si, Item> where
    Si: Unpin + Sink<Item> + ?Sized, [−]

[+] Show hidden undocumented items

type Output = Result<(), <Si as Sink<Item>>::SinkError>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Send<'_, Si, Item>>,
    cx: &mut Context
) -> Poll<<Send<'_, Si, Item> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'_, Si, St> Future for SendAll<'_, Si, St> where
    Si: Sink<<St as Stream>::Item> + Unpin + ?Sized,
    St: Stream + Unpin + ?Sized, [−]

[+] Show hidden undocumented items

type Output = Result<(), <Si as Sink<<St as Stream>::Item>>::SinkError>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut SendAll<'_, Si, St>>,
    cx: &mut Context
) -> Poll<<SendAll<'_, Si, St> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'_, St> Future for Next<'_, St> where
    St: Unpin + Stream, [−]

[+] Show hidden undocumented items

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

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Next<'_, St>>,
    cx: &mut Context
) -> Poll<<Next<'_, St> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'_, St> Future for TryNext<'_, St> where
    St: Unpin + TryStream, [−]

[+] Show hidden undocumented items

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

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut TryNext<'_, St>>,
    cx: &mut Context
) -> Poll<<TryNext<'_, St> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'_, W> Future for futures::io::Close<'_, W> where
    W: Unpin + AsyncWrite + ?Sized, [−]

[+] Show hidden undocumented items

type Output = Result<(), Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Close<'_, W>>,
    cx: &mut Context
) -> Poll<<Close<'_, W> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'_, W> Future for futures::io::Flush<'_, W> where
    W: AsyncWrite + Unpin + ?Sized, [−]

[+] Show hidden undocumented items

type Output = Result<(), Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Flush<'_, W>>,
    cx: &mut Context
) -> Poll<<Flush<'_, W> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'_, W> Future for WriteAll<'_, W> where
    W: Unpin + AsyncWrite + ?Sized, [−]

[+] Show hidden undocumented items

type Output = Result<(), Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut WriteAll<'_, W>>,
    cx: &mut Context
) -> Poll<Result<(), Error>>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'a, St> Future for SelectNextSome<'a, St> where
    St: Unpin + Stream + FusedStream, [−]

[+] Show hidden undocumented items

type Output = <St as Stream>::Item

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut SelectNextSome<'a, St>>,
    cx: &mut Context
) -> Poll<<SelectNextSome<'a, St> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'a, T> Future for FutureObj<'a, T>[−]

[+] Show hidden undocumented items

type Output = T

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(self: Pin<&mut FutureObj<'a, T>>, cx: &mut Context) -> Poll<T>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'a, T> Future for LocalFutureObj<'a, T>[−]

[+] Show hidden undocumented items

type Output = T

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(self: Pin<&mut LocalFutureObj<'a, T>>, cx: &mut Context) -> Poll<T>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<'a, T> Future for MutexLockFuture<'a, T>[−]

[+] Show hidden undocumented items

type Output = MutexGuard<'a, T>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut MutexLockFuture<'a, T>>,
    cx: &mut Context
) -> Poll<<MutexLockFuture<'a, T> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<F> Future for JoinAll<F> where
    F: Future, [−]

[+] Show hidden undocumented items

type Output = Vec<<F as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut JoinAll<F>>,
    cx: &mut Context
) -> Poll<<JoinAll<F> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<F> Future for OptionFuture<F> where
    F: Future, [−]

[+] Show hidden undocumented items

type Output = Option<<F as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut OptionFuture<F>>,
    cx: &mut Context
) -> Poll<<OptionFuture<F> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<F> Future for TryJoinAll<F> where
    F: TryFuture, [−]

[+] Show hidden undocumented items

type Output = Result<Vec<<F as TryFuture>::Ok>, <F as TryFuture>::Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut TryJoinAll<F>>,
    cx: &mut Context
) -> Poll<<TryJoinAll<F> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut> Future for MaybeDone<Fut> where
    Fut: Future, [−]

[+] Show hidden undocumented items

type Output = ()

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut MaybeDone<Fut>>,
    cx: &mut Context
) -> Poll<<MaybeDone<Fut> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut> Future for Compat01As03<Fut> where
    Fut: Future, [−]

[+] Show hidden undocumented items

type Output = Result<<Fut as Future>::Item, <Fut as Future>::Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Compat01As03<Fut>>,
    cx: &mut Context
) -> Poll<<Compat01As03<Fut> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut> Future for Abortable<Fut> where
    Fut: Future, [−]

[+] Show hidden undocumented items

type Output = Result<<Fut as Future>::Output, Aborted>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Abortable<Fut>>,
    cx: &mut Context
) -> Poll<<Abortable<Fut> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut> Future for CatchUnwind<Fut> where
    Fut: Future + UnwindSafe, [−]

[+] Show hidden undocumented items

type Output = Result<<Fut as Future>::Output, Box<dyn Any + 'static + Send>>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut CatchUnwind<Fut>>,
    cx: &mut Context
) -> Poll<<CatchUnwind<Fut> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut> Future for Flatten<Fut> where
    Fut: Future,
    <Fut as Future>::Output: Future, [−]

[+] Show hidden undocumented items

type Output = <<Fut as Future>::Output as Future>::Output

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Flatten<Fut>>,
    cx: &mut Context
) -> Poll<<Flatten<Fut> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut> Future for Fuse<Fut> where
    Fut: Future, [−]

[+] Show hidden undocumented items

type Output = <Fut as Future>::Output

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Fuse<Fut>>,
    cx: &mut Context
) -> Poll<<Fut as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut> Future for IntoFuture<Fut> where
    Fut: TryFuture, [−]

[+] Show hidden undocumented items

type Output = Result<<Fut as TryFuture>::Ok, <Fut as TryFuture>::Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut IntoFuture<Fut>>,
    cx: &mut Context
) -> Poll<<IntoFuture<Fut> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut> Future for Remote<Fut> where
    Fut: Future, [−]

[+] Show hidden undocumented items

type Output = ()

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(self: Pin<&mut Remote<Fut>>, cx: &mut Context) -> Poll<()>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut> Future for Shared<Fut> where
    Fut: Future,
    <Fut as Future>::Output: Clone, [−]

[+] Show hidden undocumented items

type Output = <Fut as Future>::Output

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Shared<Fut>>,
    cx: &mut Context
) -> Poll<<Shared<Fut> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut, E> Future for ErrInto<Fut, E> where
    Fut: TryFuture,
    <Fut as TryFuture>::Error: Into<E>, [−]

[+] Show hidden undocumented items

type Output = Result<<Fut as TryFuture>::Ok, E>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut ErrInto<Fut, E>>,
    cx: &mut Context
) -> Poll<<ErrInto<Fut, E> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut, F> Future for Inspect<Fut, F> where
    F: FnOnce(&<Fut as Future>::Output),
    Fut: Future, [−]

[+] Show hidden undocumented items

type Output = <Fut as Future>::Output

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Inspect<Fut, F>>,
    cx: &mut Context
) -> Poll<<Fut as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut, F> Future for UnwrapOrElse<Fut, F> where
    F: FnOnce(<Fut as TryFuture>::Error) -> <Fut as TryFuture>::Ok,
    Fut: TryFuture, [−]

[+] Show hidden undocumented items

type Output = <Fut as TryFuture>::Ok

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut UnwrapOrElse<Fut, F>>,
    cx: &mut Context
) -> Poll<<UnwrapOrElse<Fut, F> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut, F, E> Future for MapErr<Fut, F> where
    F: FnOnce(<Fut as TryFuture>::Error) -> E,
    Fut: TryFuture, [−]

[+] Show hidden undocumented items

type Output = Result<<Fut as TryFuture>::Ok, E>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut MapErr<Fut, F>>,
    cx: &mut Context
) -> Poll<<MapErr<Fut, F> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut, F, T> Future for Map<Fut, F> where
    F: FnOnce(<Fut as Future>::Output) -> T,
    Fut: Future, [−]

[+] Show hidden undocumented items

type Output = T

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(self: Pin<&mut Map<Fut, F>>, cx: &mut Context) -> Poll<T>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut, F, T> Future for MapOk<Fut, F> where
    F: FnOnce(<Fut as TryFuture>::Ok) -> T,
    Fut: TryFuture, [−]

[+] Show hidden undocumented items

type Output = Result<T, <Fut as TryFuture>::Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut MapOk<Fut, F>>,
    cx: &mut Context
) -> Poll<<MapOk<Fut, F> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut1, Fut2> Future for Join<Fut1, Fut2> where
    Fut1: Future,
    Fut2: Future, [−]

[+] Show hidden undocumented items

type Output = (<Fut1 as Future>::Output, <Fut2 as Future>::Output)

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Join<Fut1, Fut2>>,
    cx: &mut Context
) -> Poll<<Join<Fut1, Fut2> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut1, Fut2> Future for TryJoin<Fut1, Fut2> where
    Fut1: TryFuture,
    Fut2: TryFuture<Error = <Fut1 as TryFuture>::Error>, [−]

[+] Show hidden undocumented items

type Output = Result<(<Fut1 as TryFuture>::Ok, <Fut2 as TryFuture>::Ok), <Fut1 as TryFuture>::Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut TryJoin<Fut1, Fut2>>,
    cx: &mut Context
) -> Poll<<TryJoin<Fut1, Fut2> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut1, Fut2, F> Future for AndThen<Fut1, Fut2, F> where
    F: FnOnce(<Fut1 as TryFuture>::Ok) -> Fut2,
    Fut1: TryFuture,
    Fut2: TryFuture<Error = <Fut1 as TryFuture>::Error>, [−]

[+] Show hidden undocumented items

type Output = Result<<Fut2 as TryFuture>::Ok, <Fut2 as TryFuture>::Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut AndThen<Fut1, Fut2, F>>,
    cx: &mut Context
) -> Poll<<AndThen<Fut1, Fut2, F> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut1, Fut2, F> Future for OrElse<Fut1, Fut2, F> where
    F: FnOnce(<Fut1 as TryFuture>::Error) -> Fut2,
    Fut1: TryFuture,
    Fut2: TryFuture<Ok = <Fut1 as TryFuture>::Ok>, [−]

[+] Show hidden undocumented items

type Output = Result<<Fut2 as TryFuture>::Ok, <Fut2 as TryFuture>::Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut OrElse<Fut1, Fut2, F>>,
    cx: &mut Context
) -> Poll<<OrElse<Fut1, Fut2, F> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut1, Fut2, F> Future for Then<Fut1, Fut2, F> where
    F: FnOnce(<Fut1 as Future>::Output) -> Fut2,
    Fut1: Future,
    Fut2: Future, [−]

[+] Show hidden undocumented items

type Output = <Fut2 as Future>::Output

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Then<Fut1, Fut2, F>>,
    cx: &mut Context
) -> Poll<<Fut2 as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut1, Fut2, Fut3> Future for Join3<Fut1, Fut2, Fut3> where
    Fut1: Future,
    Fut2: Future,
    Fut3: Future, [−]

[+] Show hidden undocumented items

type Output = (<Fut1 as Future>::Output, <Fut2 as Future>::Output, <Fut3 as Future>::Output)

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Join3<Fut1, Fut2, Fut3>>,
    cx: &mut Context
) -> Poll<<Join3<Fut1, Fut2, Fut3> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut1, Fut2, Fut3> Future for TryJoin3<Fut1, Fut2, Fut3> where
    Fut1: TryFuture,
    Fut2: TryFuture<Error = <Fut1 as TryFuture>::Error>,
    Fut3: TryFuture<Error = <Fut1 as TryFuture>::Error>, [−]

[+] Show hidden undocumented items

type Output = Result<(<Fut1 as TryFuture>::Ok, <Fut2 as TryFuture>::Ok, <Fut3 as TryFuture>::Ok), <Fut1 as TryFuture>::Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut TryJoin3<Fut1, Fut2, Fut3>>,
    cx: &mut Context
) -> Poll<<TryJoin3<Fut1, Fut2, Fut3> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut1, Fut2, Fut3, Fut4> Future for Join4<Fut1, Fut2, Fut3, Fut4> where
    Fut1: Future,
    Fut2: Future,
    Fut3: Future,
    Fut4: Future, [−]

[+] Show hidden undocumented items

type Output = (<Fut1 as Future>::Output, <Fut2 as Future>::Output, <Fut3 as Future>::Output, <Fut4 as Future>::Output)

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Join4<Fut1, Fut2, Fut3, Fut4>>,
    cx: &mut Context
) -> Poll<<Join4<Fut1, Fut2, Fut3, Fut4> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut1, Fut2, Fut3, Fut4> Future for TryJoin4<Fut1, Fut2, Fut3, Fut4> where
    Fut1: TryFuture,
    Fut2: TryFuture<Error = <Fut1 as TryFuture>::Error>,
    Fut3: TryFuture<Error = <Fut1 as TryFuture>::Error>,
    Fut4: TryFuture<Error = <Fut1 as TryFuture>::Error>, [−]

[+] Show hidden undocumented items

type Output = Result<(<Fut1 as TryFuture>::Ok, <Fut2 as TryFuture>::Ok, <Fut3 as TryFuture>::Ok, <Fut4 as TryFuture>::Ok), <Fut1 as TryFuture>::Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut TryJoin4<Fut1, Fut2, Fut3, Fut4>>,
    cx: &mut Context
) -> Poll<<TryJoin4<Fut1, Fut2, Fut3, Fut4> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut1, Fut2, Fut3, Fut4, Fut5> Future for Join5<Fut1, Fut2, Fut3, Fut4, Fut5> where
    Fut1: Future,
    Fut2: Future,
    Fut3: Future,
    Fut4: Future,
    Fut5: Future, [−]

[+] Show hidden undocumented items

type Output = (<Fut1 as Future>::Output, <Fut2 as Future>::Output, <Fut3 as Future>::Output, <Fut4 as Future>::Output, <Fut5 as Future>::Output)

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Join5<Fut1, Fut2, Fut3, Fut4, Fut5>>,
    cx: &mut Context
) -> Poll<<Join5<Fut1, Fut2, Fut3, Fut4, Fut5> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<Fut1, Fut2, Fut3, Fut4, Fut5> Future for TryJoin5<Fut1, Fut2, Fut3, Fut4, Fut5> where
    Fut1: TryFuture,
    Fut2: TryFuture<Error = <Fut1 as TryFuture>::Error>,
    Fut3: TryFuture<Error = <Fut1 as TryFuture>::Error>,
    Fut4: TryFuture<Error = <Fut1 as TryFuture>::Error>,
    Fut5: TryFuture<Error = <Fut1 as TryFuture>::Error>, [−]

[+] Show hidden undocumented items

type Output = Result<(<Fut1 as TryFuture>::Ok, <Fut2 as TryFuture>::Ok, <Fut3 as TryFuture>::Ok, <Fut4 as TryFuture>::Ok, <Fut5 as TryFuture>::Ok), <Fut1 as TryFuture>::Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut TryJoin5<Fut1, Fut2, Fut3, Fut4, Fut5>>,
    cx: &mut Context
) -> Poll<<TryJoin5<Fut1, Fut2, Fut3, Fut4, Fut5> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<R, F> Future for Lazy<F> where
    F: FnOnce(&mut Context) -> R, [−]

[+] Show hidden undocumented items

type Output = R

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(self: Pin<&mut Lazy<F>>, cx: &mut Context) -> Poll<R>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<St> Future for Concat<St> where
    St: Stream,
    <St as Stream>::Item: Extend<<<St as Stream>::Item as IntoIterator>::Item>,
    <St as Stream>::Item: IntoIterator,
    <St as Stream>::Item: Default, [−]

[+] Show hidden undocumented items

type Output = <St as Stream>::Item

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Concat<St>>,
    cx: &mut Context
) -> Poll<<Concat<St> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<St> Future for StreamFuture<St> where
    St: Unpin + Stream, [−]

[+] Show hidden undocumented items

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

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut StreamFuture<St>>,
    cx: &mut Context
) -> Poll<<StreamFuture<St> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<St, C> Future for Collect<St, C> where
    C: Default + Extend<<St as Stream>::Item>,
    St: Stream, [−]

[+] Show hidden undocumented items

type Output = C

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(self: Pin<&mut Collect<St, C>>, cx: &mut Context) -> Poll<C>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<St, C> Future for TryCollect<St, C> where
    C: Default + Extend<<St as TryStream>::Ok>,
    St: TryStream, [−]

[+] Show hidden undocumented items

type Output = Result<C, <St as TryStream>::Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut TryCollect<St, C>>,
    cx: &mut Context
) -> Poll<<TryCollect<St, C> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<St, Fut, F> Future for ForEach<St, Fut, F> where
    F: FnMut(<St as Stream>::Item) -> Fut,
    Fut: Future<Output = ()>,
    St: Stream, [−]

[+] Show hidden undocumented items

type Output = ()

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(self: Pin<&mut ForEach<St, Fut, F>>, cx: &mut Context) -> Poll<()>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<St, Fut, F> Future for ForEachConcurrent<St, Fut, F> where
    F: FnMut(<St as Stream>::Item) -> Fut,
    Fut: Future<Output = ()>,
    St: Stream, [−]

[+] Show hidden undocumented items

type Output = ()

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut ForEachConcurrent<St, Fut, F>>,
    cx: &mut Context
) -> Poll<()>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<St, Fut, F> Future for TryForEach<St, Fut, F> where
    F: FnMut(<St as TryStream>::Ok) -> Fut,
    Fut: TryFuture<Ok = (), Error = <St as TryStream>::Error>,
    St: TryStream, [−]

[+] Show hidden undocumented items

type Output = Result<(), <St as TryStream>::Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut TryForEach<St, Fut, F>>,
    cx: &mut Context
) -> Poll<<TryForEach<St, Fut, F> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<St, Fut, F> Future for TryForEachConcurrent<St, Fut, F> where
    F: FnMut(<St as TryStream>::Ok) -> Fut,
    Fut: Future<Output = Result<(), <St as TryStream>::Error>>,
    St: TryStream, [−]

[+] Show hidden undocumented items

type Output = Result<(), <St as TryStream>::Error>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut TryForEachConcurrent<St, Fut, F>>,
    cx: &mut Context
) -> Poll<<TryForEachConcurrent<St, Fut, F> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<St, Fut, T, F> Future for Fold<St, Fut, T, F> where
    F: FnMut(T, <St as Stream>::Item) -> Fut,
    Fut: Future<Output = T>,
    St: Stream, [−]

[+] Show hidden undocumented items

type Output = T

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(self: Pin<&mut Fold<St, Fut, T, F>>, cx: &mut Context) -> Poll<T>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<St, Fut, T, F> Future for TryFold<St, Fut, T, F> where
    F: FnMut(T, <St as TryStream>::Ok) -> Fut,
    Fut: TryFuture<Ok = T, Error = <St as TryStream>::Error>,
    St: TryStream, [−]

[+] Show hidden undocumented items

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

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut TryFold<St, Fut, T, F>>,
    cx: &mut Context
) -> Poll<<TryFold<St, Fut, T, F> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<St, Si, Item, E> Future for Forward<St, Si> where
    Si: Sink<Item, SinkError = E>,
    St: Stream<Item = Result<Item, E>>, [−]

[+] Show hidden undocumented items

type Output = Result<(), <Si as Sink<Item>>::SinkError>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Forward<St, Si>>,
    cx: &mut Context
) -> Poll<<Forward<St, Si> as Future>::Output>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<T> Future for Receiver<T>[−]

[+] Show hidden undocumented items

type Output = Result<T, Canceled>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(
    self: Pin<&mut Receiver<T>>,
    cx: &mut Context
) -> Poll<Result<T, Canceled>>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<T> Future for Empty<T>[−]

[+] Show hidden undocumented items

type Output = T

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(self: Pin<&mut Empty<T>>, &mut Context) -> Poll<T>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<T> Future for Ready<T>[−]

[+] Show hidden undocumented items

type Output = T

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(self: Pin<&mut Ready<T>>, _cx: &mut Context) -> Poll<T>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<T> Future for RemoteHandle<T> where
    T: 'static + Send, [−]

[+] Show hidden undocumented items

type Output = T

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(self: Pin<&mut RemoteHandle<T>>, cx: &mut Context) -> Poll<T>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<T, F> Future for PollFn<F> where
    F: FnMut(&mut Context) -> Poll<T>, [−]

[+] Show hidden undocumented items

type Output = T

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

fn poll(self: Pin<&mut PollFn<F>>, cx: &mut Context) -> Poll<T>

🔬 This is a nightly-only experimental API. (futures_api)

futures in libcore are unstable

impl<T> Future for Receiver<T>

impl<Fut: Future> Future for AssertUnmoved<Fut>

impl<Fut: Future> Future for PendingOnce<Fut>

impl<T> Future for Empty<T>

impl<R, F> Future for Lazy<F> where     F: FnOnce(&mut Context) -> R,

impl<Fut: Future> Future for MaybeDone<Fut>

impl<F: Future> Future for OptionFuture<F>

impl<T, F> Future for PollFn<F> where     F: FnMut(&mut Context) -> Poll<T>,

impl<T> Future for Ready<T>

impl<Fut1: Future, Fut2: Future> Future for Join<Fut1, Fut2>

impl<Fut1: Future, Fut2: Future, Fut3: Future> Future for Join3<Fut1, Fut2, Fut3>

impl<Fut1: Future, Fut2: Future, Fut3: Future, Fut4: Future> Future for Join4<Fut1, Fut2, Fut3, Fut4>

impl<Fut1: Future, Fut2: Future, Fut3: Future, Fut4: Future, Fut5: Future> Future for Join5<Fut1, Fut2, Fut3, Fut4, Fut5>

impl<F> Future for JoinAll<F> where     F: Future,

impl<Fut> Future for Flatten<Fut> where     Fut: Future,     Fut::Output: Future,

impl<Fut: Future> Future for Fuse<Fut>

impl<Fut, F, T> Future for Map<Fut, F> where     Fut: Future,     F: FnOnce(Fut::Output) -> T,

impl<Fut1, Fut2, F> Future for Then<Fut1, Fut2, F> where     Fut1: Future,     Fut2: Future,     F: FnOnce(Fut1::Output) -> Fut2,

impl<Fut, F> Future for Inspect<Fut, F> where     Fut: Future,     F: FnOnce(&Fut::Output),

impl<Fut, T> Future for UnitError<Fut> where     Fut: Future<Output = T>,

impl<Fut> Future for Abortable<Fut> where     Fut: Future,

impl<Fut> Future for CatchUnwind<Fut> where     Fut: Future + UnwindSafe,

impl<T: Send + 'static> Future for RemoteHandle<T>

impl<Fut: Future> Future for Remote<Fut>

impl<Fut: Future> Future for Shared<Fut> where     Fut::Output: Clone,

impl<Fut1, Fut2> Future for TryJoin<Fut1, Fut2> where     Fut1: TryFuture,     Fut2: TryFuture<Error = Fut1::Error>,

impl<Fut1, Fut2, Fut3> Future for TryJoin3<Fut1, Fut2, Fut3> where     Fut1: TryFuture,     Fut2: TryFuture<Error = Fut1::Error>,     Fut3: TryFuture<Error = Fut1::Error>,

impl<Fut1, Fut2, Fut3, Fut4> Future for TryJoin4<Fut1, Fut2, Fut3, Fut4> where     Fut1: TryFuture,     Fut2: TryFuture<Error = Fut1::Error>,     Fut3: TryFuture<Error = Fut1::Error>,     Fut4: TryFuture<Error = Fut1::Error>,

impl<Fut1, Fut2, Fut3, Fut4, Fut5> Future for TryJoin5<Fut1, Fut2, Fut3, Fut4, Fut5> where     Fut1: TryFuture,     Fut2: TryFuture<Error = Fut1::Error>,     Fut3: TryFuture<Error = Fut1::Error>,     Fut4: TryFuture<Error = Fut1::Error>,     Fut5: TryFuture<Error = Fut1::Error>,

impl<F> Future for TryJoinAll<F> where     F: TryFuture,

impl<Fut1, Fut2, F> Future for AndThen<Fut1, Fut2, F> where     Fut1: TryFuture,     Fut2: TryFuture<Error = Fut1::Error>,     F: FnOnce(Fut1::Ok) -> Fut2,

impl<Fut, E> Future for ErrInto<Fut, E> where     Fut: TryFuture,     Fut::Error: Into<E>,

impl<Fut: TryFuture> Future for IntoFuture<Fut>

impl<Fut, F, E> Future for MapErr<Fut, F> where     Fut: TryFuture,     F: FnOnce(Fut::Error) -> E,

impl<Fut, F, T> Future for MapOk<Fut, F> where     Fut: TryFuture,     F: FnOnce(Fut::Ok) -> T,

impl<Fut1, Fut2, F> Future for OrElse<Fut1, Fut2, F> where     Fut1: TryFuture,     Fut2: TryFuture<Ok = Fut1::Ok>,     F: FnOnce(Fut1::Error) -> Fut2,

impl<Fut, F> Future for UnwrapOrElse<Fut, F> where     Fut: TryFuture,     F: FnOnce(Fut::Error) -> Fut::Ok,

impl<St, C> Future for Collect<St, C> where     St: Stream,     C: Default + Extend<St::Item>,

impl<St> Future for Concat<St> where     St: Stream,     St::Item: Extend<<St::Item as IntoIterator>::Item> + IntoIterator + Default,

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

impl<St, Si, Item, E> Future for Forward<St, Si> where     Si: Sink<Item, SinkError = E>,     St: Stream<Item = Result<Item, E>>,

impl<St, Fut, F> Future for ForEach<St, Fut, F> where     St: Stream,     F: FnMut(St::Item) -> Fut,     Fut: Future<Output = ()>,

impl<St: Stream + Unpin> Future for StreamFuture<St>

impl<St: Stream + Unpin, '_> Future for Next<'_, St>

impl<'a, St: Stream + FusedStream + Unpin> Future for SelectNextSome<'a, St>

impl<St, Fut, F> Future for ForEachConcurrent<St, Fut, F> where     St: Stream,     F: FnMut(St::Item) -> Fut,     Fut: Future<Output = ()>,

impl<St: TryStream + Unpin, '_> Future for TryNext<'_, St>

impl<St, Fut, F> Future for TryForEach<St, Fut, F> where     St: TryStream,     F: FnMut(St::Ok) -> Fut,     Fut: TryFuture<Ok = (), Error = St::Error>,

impl<St, C> Future for TryCollect<St, C> where     St: TryStream,     C: Default + Extend<St::Ok>,

impl<St> Future for TryConcat<St> where     St: TryStream,     St::Ok: Extend<<St::Ok as IntoIterator>::Item> + IntoIterator + Default,

impl<St, Fut, T, F> Future for TryFold<St, Fut, T, F> where     St: TryStream,     F: FnMut(T, St::Ok) -> Fut,     Fut: TryFuture<Ok = T, Error = St::Error>,

impl<St, Fut, F> Future for TryForEachConcurrent<St, Fut, F> where     St: TryStream,     F: FnMut(St::Ok) -> Fut,     Fut: Future<Output = Result<(), St::Error>>,

impl<Si: Sink<Item> + Unpin + ?Sized, Item, '_> Future for Close<'_, Si, Item>

impl<Si: Sink<Item> + Unpin + ?Sized, Item, '_> Future for Flush<'_, Si, Item>

impl<Si: Sink<Item> + Unpin + ?Sized, Item, '_> Future for Send<'_, Si, Item>

impl<Si: ?Sized, St: ?Sized, '_> Future for SendAll<'_, Si, St> where     Si: Sink<St::Item> + Unpin,     St: Stream + Unpin,

impl<Fut: Future01> Future for Compat01As03<Fut>

impl<R: ?Sized, W: ?Sized, '_> Future for CopyInto<'_, R, W> where     R: AsyncRead + Unpin,     W: AsyncWrite + Unpin,

impl<W: ?Sized, '_> Future for Flush<'_, W> where     W: AsyncWrite + Unpin,

impl<R: AsyncRead + ?Sized + Unpin, '_> Future for Read<'_, R>

impl<R: AsyncRead + ?Sized + Unpin, '_> Future for ReadExact<'_, R>

impl<A: ?Sized, '_> Future for ReadToEnd<'_, A> where     A: AsyncRead + Unpin,

impl<W: AsyncWrite + ?Sized + Unpin, '_> Future for Close<'_, W>

impl<W: AsyncWrite + ?Sized + Unpin, '_> Future for WriteAll<'_, W>

impl<'a, T> Future for MutexLockFuture<'a, T>

impl<'a, T> Future for BiLockAcquire<'a, T>