Struct futures::prelude::future::OptionFuture

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pub struct OptionFuture<F> { /* private fields */ }

Expand description

A future representing a value which may or may not be present.

Created by the From implementation for Option.

Examples

use futures::future::OptionFuture;

let mut a: OptionFuture<_> = Some(async { 123 }).into();
assert_eq!(a.await, Some(123));

a = None.into();
assert_eq!(a.await, None);

Trait Implementations

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impl<F> Clone for OptionFuture<F> where
F: Clone,

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fn clone(&self) -> OptionFuture<F>ⓘNotable traits for OptionFuture<F>`impl<F> Future for OptionFuture<F> where F: Future, type Output = Option<<F as Future>::Output>;`

Returns a copy of the value. Read more

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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more

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impl<F> Debug for OptionFuture<F> where
F: Debug,

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

Formats the value using the given formatter. Read more

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impl<F> Default for OptionFuture<F>

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fn default() -> OptionFuture<F>ⓘNotable traits for OptionFuture<F>`impl<F> Future for OptionFuture<F> where F: Future, type Output = Option<<F as Future>::Output>;`

Returns the “default value” for a type. Read more

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impl<T> From<Option<T>> for OptionFuture<T>

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fn from(option: Option<T>) -> OptionFuture<T>ⓘNotable traits for OptionFuture<F>`impl<F> Future for OptionFuture<F> where F: Future, type Output = Option<<F as Future>::Output>;`

Performs the conversion.

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impl<F> FusedFuture for OptionFuture<F> where
F: FusedFuture,

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fn is_terminated(&self) -> bool

Returns true if the underlying future should no longer be polled.

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

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

The type of value produced on completion.

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

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

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impl<'pin, F> Unpin for OptionFuture<F> where
Origin<'__pin, F>: Unpin,

Auto Trait Implementations

impl<F> RefUnwindSafe for OptionFuture<F> where
F: RefUnwindSafe,

impl<F> Send for OptionFuture<F> where
F: Send,

impl<F> Sync for OptionFuture<F> where
F: Sync,

impl<F> UnwindSafe for OptionFuture<F> where
F: UnwindSafe,

Blanket Implementations

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impl<T> Any for T where
T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more

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impl<T> Borrow<T> for T where
T: ?Sized,

const: unstable · source

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

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impl<T> BorrowMut<T> for T where
T: ?Sized,

const: unstable · source

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

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impl<T> From<T> for T

const: unstable · source

fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> FutureExt for T where
T: Future + ?Sized,

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fn map<U, F>(self, f: F) -> Map<Self, F>ⓘNotable traits for Map<Fut, F>`impl<Fut, F> Future for Map<Fut, F> where Map<Fut, F>: Future, type Output = <Map<Fut, F> as Future>::Output;` where
F: FnOnce(Self::Output) -> U,

Map this future’s output to a different type, returning a new future of the resulting type. Read more

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fn map_into(self) -> MapInto<Self, U>ⓘNotable traits for MapInto<Fut, T>`impl<Fut, T> Future for MapInto<Fut, T> where Map<Fut, IntoFn<T>>: Future, type Output = <Map<Fut, IntoFn<T>> as Future>::Output;` where
Self::Output: Into,

Map this future’s output to a different type, returning a new future of the resulting type. Read more

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fn then<Fut, F>(self, f: F) -> Then<Self, Fut, F>ⓘNotable traits for Then<Fut1, Fut2, F>`impl<Fut1, Fut2, F> Future for Then<Fut1, Fut2, F> where Flatten<Map<Fut1, F>, Fut2>: Future, type Output = <Flatten<Map<Fut1, F>, Fut2> as Future>::Output;` where
 F: FnOnce(Self::Output) -> Fut,
 Fut: Future,

Chain on a computation for when a future finished, passing the result of the future to the provided closure f. Read more

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fn left_future(self) -> Either<Self, B>ⓘNotable traits for Either<A, B>`impl<A, B> Future for Either<A, B> where A: Future, B: Future<Output = <A as Future>::Output>, type Output = <A as Future>::Output;` where
B: Future<Output = Self::Output>,

Wrap this future in an Either future, making it the left-hand variant of that Either. Read more

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fn right_future<A>(self) -> Either<A, Self>ⓘNotable traits for Either<A, B>`impl<A, B> Future for Either<A, B> where A: Future, B: Future<Output = <A as Future>::Output>, type Output = <A as Future>::Output;` where
A: Future<Output = Self::Output>,

Wrap this future in an Either future, making it the right-hand variant of that Either. Read more

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fn into_stream(self) -> IntoStream<Self>

Convert this future into a single element stream. Read more

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fn flatten(self) -> Flatten<Self>ⓘNotable traits for Flatten<F>`impl<F> Future for Flatten<F> where F: Future, Flatten<F, <F as Future>::Output>: Future, type Output = <Flatten<F, <F as Future>::Output> as Future>::Output;` where
Self::Output: Future,

Flatten the execution of this future when the output of this future is itself another future. Read more

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fn flatten_stream(self) -> FlattenStream<Self> where
Self::Output: Stream,

Flatten the execution of this future when the successful result of this future is a stream. Read more

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fn fuse(self) -> Fuse<Self>ⓘNotable traits for Fuse<Fut>`impl<Fut> Future for Fuse<Fut> where Fut: Future, type Output = <Fut as Future>::Output;`

Fuse a future such that poll will never again be called once it has completed. This method can be used to turn any Future into a FusedFuture. Read more

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fn inspect<F>(self, f: F) -> Inspect<Self, F>ⓘNotable traits for Inspect<Fut, F>`impl<Fut, F> Future for Inspect<Fut, F> where Map<Fut, InspectFn<F>>: Future, type Output = <Map<Fut, InspectFn<F>> as Future>::Output;` where
F: FnOnce(&Self::Output),

Do something with the output of a future before passing it on. Read more

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fn catch_unwind(self) -> CatchUnwind<Self>ⓘNotable traits for CatchUnwind<Fut>`impl<Fut> Future for CatchUnwind<Fut> where Fut: Future + UnwindSafe, type Output = Result<<Fut as Future>::Output, Box<dyn Any + Send + 'static, Global>>;` where
Self: UnwindSafe,

Catches unwinding panics while polling the future. Read more

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fn shared(self) -> Shared<Self>ⓘNotable traits for Shared<Fut>`impl<Fut> Future for Shared<Fut> where Fut: Future, <Fut as Future>::Output: Clone, type Output = <Fut as Future>::Output;` where
Self::Output: Clone,

Create a cloneable handle to this future where all handles will resolve to the same result. Read more

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fn remote_handle(self) -> (Remote<Self>, RemoteHandle<Self::Output>)

Turn this future into a future that yields () on completion and sends its output to another future on a separate task. Read more

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fn boxed<'a>(
 self
) -> Pin<Box<dyn Future<Output = Self::Output> + Send + 'a, Global>>ⓘNotable traits for Pin`impl Future for Pin where P: DerefMut, ::Target: Future, type Output = <::Target as Future>::Output;` where
 Self: 'a + Send,

Wrap the future in a Box, pinning it. Read more

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fn boxed_local<'a>(
 self
) -> Pin<Box<dyn Future<Output = Self::Output> + 'a, Global>>ⓘNotable traits for Pin`impl Future for Pin where P: DerefMut, ::Target: Future, type Output = <::Target as Future>::Output;` where
 Self: 'a,

Wrap the future in a Box, pinning it. Read more

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fn unit_error(self) -> UnitError<Self>ⓘNotable traits for UnitError<Fut>`impl<Fut> Future for UnitError<Fut> where Map<Fut, OkFn<()>>: Future, type Output = <Map<Fut, OkFn<()>> as Future>::Output;`

Turns a Future<Output = T> into a TryFuture<Ok = T, Error = ()>. Read more

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fn never_error(self) -> NeverError<Self>ⓘNotable traits for NeverError<Fut>`impl<Fut> Future for NeverError<Fut> where Map<Fut, OkFn<Infallible>>: Future, type Output = <Map<Fut, OkFn<Infallible>> as Future>::Output;`

Turns a Future<Output = T> into a TryFuture<Ok = T, Error = Never>. Read more

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fn poll_unpin(&mut self, cx: &mut Context<'_>) -> Poll<Self::Output> where
Self: Unpin,

A convenience for calling Future::poll on Unpin future types.

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fn now_or_never(self) -> Option<Self::Output>

Evaluates and consumes the future, returning the resulting output if the future is ready after the first call to Future::poll. Read more

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impl<T, U> Into for T where
U: From<T>,

const: unstable · source

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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

type Output = <F as Future>::Output

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

The output that the future will produce on completion.

type IntoFuture = F

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

Which kind of future are we turning this into?

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fn into_future(self) -> <F as IntoFuture>::IntoFuture

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

Creates a future from a value.

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impl<T> ToOwned for T where
T: Clone,

type Owned = T

The resulting type after obtaining ownership.

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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more

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fn clone_into(&self, target: &mut T)

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

Uses borrowed data to replace owned data, usually by cloning. Read more

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impl<T, U> TryFrom for T where
U: Into<T>,

type Error = Infallible

The type returned in the event of a conversion error.

const: unstable · source

fn try_from(value: U) -> Result<T, <T as TryFrom>::Error>

Performs the conversion.

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impl<T, U> TryInto for T where
U: TryFrom<T>,

type Error = >::Error

The type returned in the event of a conversion error.

const: unstable · source

fn try_into(self) -> Result<U, >::Error>

Performs the conversion.

Struct futures::prelude::future::OptionFuture

Examples

Trait Implementations

impl<F> Clone for OptionFuture<F> where F: Clone,

fn clone(&self) -> OptionFuture<F>ⓘNotable traits for OptionFuture<F>impl<F> Future for OptionFuture<F> where F: Future, type Output = Option<<F as Future>::Output>;

fn clone_from(&mut self, source: &Self)

impl<F> Debug for OptionFuture<F> where F: Debug,

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

impl<F> Default for OptionFuture<F>

fn default() -> OptionFuture<F>ⓘNotable traits for OptionFuture<F>impl<F> Future for OptionFuture<F> where F: Future, type Output = Option<<F as Future>::Output>;

impl<T> From<Option<T>> for OptionFuture<T>

fn from(option: Option<T>) -> OptionFuture<T>ⓘNotable traits for OptionFuture<F>impl<F> Future for OptionFuture<F> where F: Future, type Output = Option<<F as Future>::Output>;

impl<F> FusedFuture for OptionFuture<F> where F: FusedFuture,

fn is_terminated(&self) -> bool

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

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

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

impl<'__pin, F> Unpin for OptionFuture<F> where __Origin<'__pin, F>: Unpin,

Auto Trait Implementations

impl<F> RefUnwindSafe for OptionFuture<F> where F: RefUnwindSafe,

impl<F> Send for OptionFuture<F> where F: Send,

impl<F> Sync for OptionFuture<F> where F: Sync,

impl<F> UnwindSafe for OptionFuture<F> where F: UnwindSafe,

Blanket Implementations

impl<T> Any for T where T: 'static + ?Sized,

fn type_id(&self) -> TypeId

impl<T> Borrow<T> for T where T: ?Sized,

fn borrow(&self) -> &T

impl<T> BorrowMut<T> for T where T: ?Sized,

fn borrow_mut(&mut self) -> &mut T

impl<T> From<T> for T

fn from(t: T) -> T

impl<T> FutureExt for T where T: Future + ?Sized,

fn map<U, F>(self, f: F) -> Map<Self, F>ⓘNotable traits for Map<Fut, F>impl<Fut, F> Future for Map<Fut, F> where Map<Fut, F>: Future, type Output = <Map<Fut, F> as Future>::Output; where F: FnOnce(Self::Output) -> U,

fn map_into<U>(self) -> MapInto<Self, U>ⓘNotable traits for MapInto<Fut, T>impl<Fut, T> Future for MapInto<Fut, T> where Map<Fut, IntoFn<T>>: Future, type Output = <Map<Fut, IntoFn<T>> as Future>::Output; where Self::Output: Into<U>,

fn then<Fut, F>(self, f: F) -> Then<Self, Fut, F>ⓘNotable traits for Then<Fut1, Fut2, F>impl<Fut1, Fut2, F> Future for Then<Fut1, Fut2, F> where Flatten<Map<Fut1, F>, Fut2>: Future, type Output = <Flatten<Map<Fut1, F>, Fut2> as Future>::Output; where F: FnOnce(Self::Output) -> Fut, Fut: Future,

fn left_future<B>(self) -> Either<Self, B>ⓘNotable traits for Either<A, B>impl<A, B> Future for Either<A, B> where A: Future, B: Future<Output = <A as Future>::Output>, type Output = <A as Future>::Output; where B: Future<Output = Self::Output>,

fn right_future<A>(self) -> Either<A, Self>ⓘNotable traits for Either<A, B>impl<A, B> Future for Either<A, B> where A: Future, B: Future<Output = <A as Future>::Output>, type Output = <A as Future>::Output; where A: Future<Output = Self::Output>,

fn into_stream(self) -> IntoStream<Self>

fn flatten(self) -> Flatten<Self>ⓘNotable traits for Flatten<F>impl<F> Future for Flatten<F> where F: Future, Flatten<F, <F as Future>::Output>: Future, type Output = <Flatten<F, <F as Future>::Output> as Future>::Output; where Self::Output: Future,

fn flatten_stream(self) -> FlattenStream<Self> where Self::Output: Stream,

fn fuse(self) -> Fuse<Self>ⓘNotable traits for Fuse<Fut>impl<Fut> Future for Fuse<Fut> where Fut: Future, type Output = <Fut as Future>::Output;

fn inspect<F>(self, f: F) -> Inspect<Self, F>ⓘNotable traits for Inspect<Fut, F>impl<Fut, F> Future for Inspect<Fut, F> where Map<Fut, InspectFn<F>>: Future, type Output = <Map<Fut, InspectFn<F>> as Future>::Output; where F: FnOnce(&Self::Output),

fn catch_unwind(self) -> CatchUnwind<Self>ⓘNotable traits for CatchUnwind<Fut>impl<Fut> Future for CatchUnwind<Fut> where Fut: Future + UnwindSafe, type Output = Result<<Fut as Future>::Output, Box<dyn Any + Send + 'static, Global>>; where Self: UnwindSafe,

fn shared(self) -> Shared<Self>ⓘNotable traits for Shared<Fut>impl<Fut> Future for Shared<Fut> where Fut: Future, <Fut as Future>::Output: Clone, type Output = <Fut as Future>::Output; where Self::Output: Clone,

fn remote_handle(self) -> (Remote<Self>, RemoteHandle<Self::Output>)

fn boxed<'a>( self) -> Pin<Box<dyn Future<Output = Self::Output> + Send + 'a, Global>>ⓘNotable traits for Pin<P>impl<P> Future for Pin<P> where P: DerefMut, <P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output; where Self: 'a + Send,

fn boxed_local<'a>( self) -> Pin<Box<dyn Future<Output = Self::Output> + 'a, Global>>ⓘNotable traits for Pin<P>impl<P> Future for Pin<P> where P: DerefMut, <P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output; where Self: 'a,

fn unit_error(self) -> UnitError<Self>ⓘNotable traits for UnitError<Fut>impl<Fut> Future for UnitError<Fut> where Map<Fut, OkFn<()>>: Future, type Output = <Map<Fut, OkFn<()>> as Future>::Output;

fn never_error(self) -> NeverError<Self>ⓘNotable traits for NeverError<Fut>impl<Fut> Future for NeverError<Fut> where Map<Fut, OkFn<Infallible>>: Future, type Output = <Map<Fut, OkFn<Infallible>> as Future>::Output;

fn poll_unpin(&mut self, cx: &mut Context<'_>) -> Poll<Self::Output> where Self: Unpin,

fn now_or_never(self) -> Option<Self::Output>

impl<T, U> Into<U> for T where U: From<T>,

fn into(self) -> U

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

type Output = <F as Future>::Output

type IntoFuture = F

fn into_future(self) -> <F as IntoFuture>::IntoFuture

impl<T> ToOwned for T where T: Clone,

type Owned = T

fn to_owned(&self) -> T

fn clone_into(&self, target: &mut T)

impl<T, U> TryFrom<U> for T where U: Into<T>,

type Error = Infallible

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

impl<T, U> TryInto<U> for T where U: TryFrom<T>,

type Error = <U as TryFrom<T>>::Error

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

impl<F> Clone for OptionFuture<F> where
F: Clone,

fn clone(&self) -> OptionFuture<F>ⓘNotable traits for OptionFuture<F>`impl<F> Future for OptionFuture<F> where F: Future, type Output = Option<<F as Future>::Output>;`

impl<F> Debug for OptionFuture<F> where
F: Debug,

fn default() -> OptionFuture<F>ⓘNotable traits for OptionFuture<F>`impl<F> Future for OptionFuture<F> where F: Future, type Output = Option<<F as Future>::Output>;`

fn from(option: Option<T>) -> OptionFuture<T>ⓘNotable traits for OptionFuture<F>`impl<F> Future for OptionFuture<F> where F: Future, type Output = Option<<F as Future>::Output>;`

impl<F> FusedFuture for OptionFuture<F> where
F: FusedFuture,

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

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

impl<'pin, F> Unpin for OptionFuture<F> where
Origin<'__pin, F>: Unpin,

impl<F> RefUnwindSafe for OptionFuture<F> where
F: RefUnwindSafe,

impl<F> Send for OptionFuture<F> where
F: Send,

impl<F> Sync for OptionFuture<F> where
F: Sync,

impl<F> UnwindSafe for OptionFuture<F> where
F: UnwindSafe,

impl<T> Any for T where
T: 'static + ?Sized,

impl<T> Borrow<T> for T where
T: ?Sized,

impl<T> BorrowMut<T> for T where
T: ?Sized,

impl<T> FutureExt for T where
T: Future + ?Sized,

fn map<U, F>(self, f: F) -> Map<Self, F>ⓘNotable traits for Map<Fut, F>`impl<Fut, F> Future for Map<Fut, F> where Map<Fut, F>: Future, type Output = <Map<Fut, F> as Future>::Output;` where
F: FnOnce(Self::Output) -> U,

fn map_into<U>(self) -> MapInto<Self, U>ⓘNotable traits for MapInto<Fut, T>`impl<Fut, T> Future for MapInto<Fut, T> where Map<Fut, IntoFn<T>>: Future, type Output = <Map<Fut, IntoFn<T>> as Future>::Output;` where
Self::Output: Into<U>,

fn then<Fut, F>(self, f: F) -> Then<Self, Fut, F>ⓘNotable traits for Then<Fut1, Fut2, F>`impl<Fut1, Fut2, F> Future for Then<Fut1, Fut2, F> where Flatten<Map<Fut1, F>, Fut2>: Future, type Output = <Flatten<Map<Fut1, F>, Fut2> as Future>::Output;` where
F: FnOnce(Self::Output) -> Fut,
Fut: Future,

fn left_future<B>(self) -> Either<Self, B>ⓘNotable traits for Either<A, B>`impl<A, B> Future for Either<A, B> where A: Future, B: Future<Output = <A as Future>::Output>, type Output = <A as Future>::Output;` where
B: Future<Output = Self::Output>,

fn right_future<A>(self) -> Either<A, Self>ⓘNotable traits for Either<A, B>`impl<A, B> Future for Either<A, B> where A: Future, B: Future<Output = <A as Future>::Output>, type Output = <A as Future>::Output;` where
A: Future<Output = Self::Output>,

fn flatten(self) -> Flatten<Self>ⓘNotable traits for Flatten<F>`impl<F> Future for Flatten<F> where F: Future, Flatten<F, <F as Future>::Output>: Future, type Output = <Flatten<F, <F as Future>::Output> as Future>::Output;` where
Self::Output: Future,

fn flatten_stream(self) -> FlattenStream<Self> where
Self::Output: Stream,

fn fuse(self) -> Fuse<Self>ⓘNotable traits for Fuse<Fut>`impl<Fut> Future for Fuse<Fut> where Fut: Future, type Output = <Fut as Future>::Output;`

fn inspect<F>(self, f: F) -> Inspect<Self, F>ⓘNotable traits for Inspect<Fut, F>`impl<Fut, F> Future for Inspect<Fut, F> where Map<Fut, InspectFn<F>>: Future, type Output = <Map<Fut, InspectFn<F>> as Future>::Output;` where
F: FnOnce(&Self::Output),

fn catch_unwind(self) -> CatchUnwind<Self>ⓘNotable traits for CatchUnwind<Fut>`impl<Fut> Future for CatchUnwind<Fut> where Fut: Future + UnwindSafe, type Output = Result<<Fut as Future>::Output, Box<dyn Any + Send + 'static, Global>>;` where
Self: UnwindSafe,

fn shared(self) -> Shared<Self>ⓘNotable traits for Shared<Fut>`impl<Fut> Future for Shared<Fut> where Fut: Future, <Fut as Future>::Output: Clone, type Output = <Fut as Future>::Output;` where
Self::Output: Clone,

fn boxed<'a>(
self
) -> Pin<Box<dyn Future<Output = Self::Output> + Send + 'a, Global>>ⓘNotable traits for Pin<P>`impl<P> Future for Pin<P> where P: DerefMut, <P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output;` where
Self: 'a + Send,

fn boxed_local<'a>(
self
) -> Pin<Box<dyn Future<Output = Self::Output> + 'a, Global>>ⓘNotable traits for Pin<P>`impl<P> Future for Pin<P> where P: DerefMut, <P as Deref>::Target: Future, type Output = <<P as Deref>::Target as Future>::Output;` where
Self: 'a,

fn unit_error(self) -> UnitError<Self>ⓘNotable traits for UnitError<Fut>`impl<Fut> Future for UnitError<Fut> where Map<Fut, OkFn<()>>: Future, type Output = <Map<Fut, OkFn<()>> as Future>::Output;`

fn never_error(self) -> NeverError<Self>ⓘNotable traits for NeverError<Fut>`impl<Fut> Future for NeverError<Fut> where Map<Fut, OkFn<Infallible>>: Future, type Output = <Map<Fut, OkFn<Infallible>> as Future>::Output;`

fn poll_unpin(&mut self, cx: &mut Context<'_>) -> Poll<Self::Output> where
Self: Unpin,

impl<T, U> Into<U> for T where
U: From<T>,

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

impl<T> ToOwned for T where
T: Clone,

impl<T, U> TryFrom<U> for T where
U: Into<T>,

impl<T, U> TryInto<U> for T where
U: TryFrom<T>,