Enum futures_util::future::MaybeDone

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pub enum MaybeDone<Fut: Future> {
    Future(Fut),
    Done(Fut::Output),
    Gone,
}

[−] Expand description

A future that may have completed.

This is created by the maybe_done() function.

Variants

Future(Fut)

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A not-yet-completed future

Done(Fut::Output)

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The output of the completed future

Gone

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The empty variant after the result of a MaybeDone has been taken using the take_output method.

Methods

impl<Fut: Future> MaybeDone<Fut>

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pub fn output_mut<'a>(self: PinMut<'a, Self>) -> Option<&'a mut Fut::Output>

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Returns an Option containing a mutable reference to the output of the future. The output of this method will be Some if and only if the inner future has been completed and take_output has not yet been called.

pub fn take_output(self: PinMut<Self>) -> Option<Fut::Output>

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Attempt to take the output of a MaybeDone without driving it towards completion.

Trait Implementations

impl<Fut: Debug + Future> Debug for MaybeDone<Fut> where     Fut::Output: Debug,

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

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Formats the value using the given formatter.

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

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

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type Output = ()

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

futures in libcore are unstable

The result of the Future.

fn poll(self: PinMut<Self>, cx: &mut Context) -> Poll<Self::Output>

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🔬 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.