Struct tor_guardmgr::GuardUsable

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pub struct GuardUsable { /* private fields */ }
Expand description

A future used to see if we have “permission” to use a guard.

For efficiency, the GuardMgr implementation sometimes gives out lower-priority guards when it is not certain whether higher-priority guards are running. After having built a circuit with such a guard, the caller must wait on this future to see whether the circuit is usable or not.

The circuit may be usable immediately (as happens if the guard was of sufficient priority, or if all higher-priority guards are known to be down). It may eventually become usable (if all of the higher-priority guards are discovered to be down). Or it may eventually become unusable (if we find a higher-priority guard that works).

Any GuardRestrictions that were used to select this guard may influence whether it is usable: if higher priority guards were ignored because of a restriction, then we might use a guard that we otherwise wouldn’t.

Trait Implementations§

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impl Future for GuardUsable

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type Output = Result<bool, Canceled>

The type of value produced on completion.
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fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::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> Unpin for GuardUsable
where __GuardUsable<'pin>: Unpin,

Auto Trait Implementations§

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,

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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,

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

Mutably borrows from an owned value. Read more
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impl<T> Conv for T

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fn conv<T>(self) -> T
where Self: Into<T>,

Converts self into T using Into<T>. Read more
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impl<T> FmtForward for T

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fn fmt_binary(self) -> FmtBinary<Self>
where Self: Binary,

Causes self to use its Binary implementation when Debug-formatted.
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fn fmt_display(self) -> FmtDisplay<Self>
where Self: Display,

Causes self to use its Display implementation when Debug-formatted.
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fn fmt_lower_exp(self) -> FmtLowerExp<Self>
where Self: LowerExp,

Causes self to use its LowerExp implementation when Debug-formatted.
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fn fmt_lower_hex(self) -> FmtLowerHex<Self>
where Self: LowerHex,

Causes self to use its LowerHex implementation when Debug-formatted.
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fn fmt_octal(self) -> FmtOctal<Self>
where Self: Octal,

Causes self to use its Octal implementation when Debug-formatted.
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fn fmt_pointer(self) -> FmtPointer<Self>
where Self: Pointer,

Causes self to use its Pointer implementation when Debug-formatted.
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fn fmt_upper_exp(self) -> FmtUpperExp<Self>
where Self: UpperExp,

Causes self to use its UpperExp implementation when Debug-formatted.
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fn fmt_upper_hex(self) -> FmtUpperHex<Self>
where Self: UpperHex,

Causes self to use its UpperHex implementation when Debug-formatted.
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fn fmt_list(self) -> FmtList<Self>
where &'a Self: for<'a> IntoIterator,

Formats each item in a sequence. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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

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

A convenience for calling Future::poll() on !Unpin types.
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fn or<F>(self, other: F) -> Or<Self, F>
where Self: Sized, F: Future<Output = Self::Output>,

Returns the result of self or other future, preferring self if both are ready. Read more
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fn race<F>(self, other: F) -> Race<Self, F>
where Self: Sized, F: Future<Output = Self::Output>,

Available on crate feature std only.
Returns the result of self or other future, with no preference if both are ready. Read more
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fn catch_unwind(self) -> CatchUnwind<Self>
where Self: Sized + UnwindSafe,

Available on crate feature std only.
Catches panics while polling the future. Read more
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fn boxed<'a>(self) -> Pin<Box<dyn Future<Output = Self::Output> + Send + 'a>>
where Self: Sized + Send + 'a,

Available on crate feature alloc only.
Boxes the future and changes its type to dyn Future + Send + 'a. Read more
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fn boxed_local<'a>(self) -> Pin<Box<dyn Future<Output = Self::Output> + 'a>>
where Self: Sized + 'a,

Available on crate feature alloc only.
Boxes the future and changes its type to dyn Future + 'a. Read more
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impl<F> FutureExt for F
where F: Future + ?Sized,

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

A convenience for calling Future::poll() on !Unpin types.
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fn or<F>(self, other: F) -> Or<Self, F>
where Self: Sized, F: Future<Output = Self::Output>,

Returns the result of self or other future, preferring self if both are ready. Read more
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fn race<F>(self, other: F) -> Race<Self, F>
where Self: Sized, F: Future<Output = Self::Output>,

Available on crate features std and race only.
Returns the result of self or other future, with no preference if both are ready. Read more
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fn catch_unwind(self) -> CatchUnwind<Self>
where Self: Sized + UnwindSafe,

Available on crate feature std only.
Catches panics while polling the future. Read more
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fn boxed<'a>(self) -> Pin<Box<dyn Future<Output = Self::Output> + Send + 'a>>
where Self: Sized + Send + 'a,

Available on crate feature alloc only.
Boxes the future and changes its type to dyn Future + Send + 'a. Read more
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fn boxed_local<'a>(self) -> Pin<Box<dyn Future<Output = Self::Output> + 'a>>
where Self: Sized + 'a,

Available on crate feature alloc only.
Boxes the future and changes its type to dyn Future + 'a. Read more
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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>
where F: FnOnce(Self::Output) -> U, Self: Sized,

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<U>(self) -> MapInto<Self, U>
where Self::Output: Into<U>, Self: Sized,

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>
where F: FnOnce(Self::Output) -> Fut, Fut: Future, Self: Sized,

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<B>(self) -> Either<Self, B>
where B: Future<Output = Self::Output>, Self: Sized,

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>
where A: Future<Output = Self::Output>, Self: Sized,

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>
where Self: Sized,

Convert this future into a single element stream. Read more
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fn flatten(self) -> Flatten<Self>
where Self::Output: Future, Self: Sized,

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, Self: Sized,

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>
where Self: Sized,

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>
where F: FnOnce(&Self::Output), Self: Sized,

Do something with the output of a future before passing it on. Read more
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fn catch_unwind(self) -> CatchUnwind<Self>
where Self: Sized + UnwindSafe,

Available on crate feature std only.
Catches unwinding panics while polling the future. Read more
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fn shared(self) -> Shared<Self>
where Self: Sized, Self::Output: Clone,

Available on crate feature std only.
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>)
where Self: Sized,

Available on crate features channel and std only.
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>>
where Self: Sized + Send + 'a,

Available on crate feature alloc only.
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>>
where Self: Sized + 'a,

Available on crate feature alloc only.
Wrap the future in a Box, pinning it. Read more
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fn unit_error(self) -> UnitError<Self>
where Self: Sized,

Turns a Future<Output = T> into a TryFuture<Ok = T, Error = ()>.
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fn never_error(self) -> NeverError<Self>
where Self: Sized,

Turns a Future<Output = T> into a TryFuture<Ok = T, Error = Never>.
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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>
where Self: Sized,

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

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fn delay(self, dur: Duration) -> DelayFuture<Self>
where Self: Sized,

Available on crate feature unstable only.
Returns a Future that delays execution for a specified time. Read more
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fn flatten(self) -> FlattenFuture<Self, <Self::Output as IntoFuture>::Future>
where Self: Sized, Self::Output: IntoFuture,

Available on crate feature unstable only.
Flatten out the execution of this future when the result itself can be converted into another future. Read more
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fn race<F>(self, other: F) -> Race<Self, F>
where Self: Sized + Future, F: Future<Output = Self::Output>,

Available on crate feature unstable only.
Waits for one of two similarly-typed futures to complete. Read more
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fn try_race<F, T, E>(self, other: F) -> TryRace<Self, F>
where Self: Sized + Future<Output = Result<T, E>>, F: Future<Output = Self::Output>,

Available on crate feature unstable only.
Waits for one of two similarly-typed fallible futures to complete. Read more
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fn join<F>(self, other: F) -> Join<Self, F>
where Self: Sized + Future, F: Future,

Available on crate features unstable or docs only.
Waits for two similarly-typed futures to complete. Read more
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fn try_join<F, A, B, E>(self, other: F) -> TryJoin<Self, F>
where Self: Sized + Future<Output = Result<A, E>>, F: Future<Output = Result<B, E>>,

Available on crate features unstable or docs only.
Waits for two similarly-typed fallible futures to complete. Read more
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fn timeout(self, dur: Duration) -> TimeoutFuture<Self>
where Self: Sized,

Available on crate features default and unstable, or crate feature docs only.
Waits for both the future and a timeout, if the timeout completes before the future, it returns a TimeoutError. Read more
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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided [Span], returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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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<T> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<F> IntoFuture for F
where F: Future,

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type Output = <F as Future>::Output

The output that the future will produce on completion.
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type IntoFuture = F

Which kind of future are we turning this into?
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fn into_future(self) -> <F as IntoFuture>::IntoFuture

Creates a future from a value. Read more
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impl<T> IntoFuture for T
where T: Future,

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type Output = <T as Future>::Output

The type of value produced on completion.
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type Future = T

Which kind of future are we turning this into?
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fn into_future(self) -> <T as IntoFuture>::Future

Create a future from a value
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impl<T> Pipe for T
where T: ?Sized,

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fn pipe<R>(self, func: impl FnOnce(Self) -> R) -> R
where Self: Sized,

Pipes by value. This is generally the method you want to use. Read more
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fn pipe_ref<'a, R>(&'a self, func: impl FnOnce(&'a Self) -> R) -> R
where R: 'a,

Borrows self and passes that borrow into the pipe function. Read more
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fn pipe_ref_mut<'a, R>(&'a mut self, func: impl FnOnce(&'a mut Self) -> R) -> R
where R: 'a,

Mutably borrows self and passes that borrow into the pipe function. Read more
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fn pipe_borrow<'a, B, R>(&'a self, func: impl FnOnce(&'a B) -> R) -> R
where Self: Borrow<B>, B: 'a + ?Sized, R: 'a,

Borrows self, then passes self.borrow() into the pipe function. Read more
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fn pipe_borrow_mut<'a, B, R>( &'a mut self, func: impl FnOnce(&'a mut B) -> R ) -> R
where Self: BorrowMut<B>, B: 'a + ?Sized, R: 'a,

Mutably borrows self, then passes self.borrow_mut() into the pipe function. Read more
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fn pipe_as_ref<'a, U, R>(&'a self, func: impl FnOnce(&'a U) -> R) -> R
where Self: AsRef<U>, U: 'a + ?Sized, R: 'a,

Borrows self, then passes self.as_ref() into the pipe function.
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fn pipe_as_mut<'a, U, R>(&'a mut self, func: impl FnOnce(&'a mut U) -> R) -> R
where Self: AsMut<U>, U: 'a + ?Sized, R: 'a,

Mutably borrows self, then passes self.as_mut() into the pipe function.
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fn pipe_deref<'a, T, R>(&'a self, func: impl FnOnce(&'a T) -> R) -> R
where Self: Deref<Target = T>, T: 'a + ?Sized, R: 'a,

Borrows self, then passes self.deref() into the pipe function.
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fn pipe_deref_mut<'a, T, R>( &'a mut self, func: impl FnOnce(&'a mut T) -> R ) -> R
where Self: DerefMut<Target = T> + Deref, T: 'a + ?Sized, R: 'a,

Mutably borrows self, then passes self.deref_mut() into the pipe function.
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impl<T> Same for T

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type Output = T

Should always be Self
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impl<T> Tap for T

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fn tap(self, func: impl FnOnce(&Self)) -> Self

Immutable access to a value. Read more
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fn tap_mut(self, func: impl FnOnce(&mut Self)) -> Self

Mutable access to a value. Read more
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fn tap_borrow<B>(self, func: impl FnOnce(&B)) -> Self
where Self: Borrow<B>, B: ?Sized,

Immutable access to the Borrow<B> of a value. Read more
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fn tap_borrow_mut<B>(self, func: impl FnOnce(&mut B)) -> Self
where Self: BorrowMut<B>, B: ?Sized,

Mutable access to the BorrowMut<B> of a value. Read more
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fn tap_ref<R>(self, func: impl FnOnce(&R)) -> Self
where Self: AsRef<R>, R: ?Sized,

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fn tap_ref_mut<R>(self, func: impl FnOnce(&mut R)) -> Self
where Self: AsMut<R>, R: ?Sized,

Mutable access to the AsMut<R> view of a value. Read more
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fn tap_deref<T>(self, func: impl FnOnce(&T)) -> Self
where Self: Deref<Target = T>, T: ?Sized,

Immutable access to the Deref::Target of a value. Read more
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fn tap_deref_mut<T>(self, func: impl FnOnce(&mut T)) -> Self
where Self: DerefMut<Target = T> + Deref, T: ?Sized,

Mutable access to the Deref::Target of a value. Read more
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fn tap_dbg(self, func: impl FnOnce(&Self)) -> Self

Calls .tap() only in debug builds, and is erased in release builds.
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fn tap_mut_dbg(self, func: impl FnOnce(&mut Self)) -> Self

Calls .tap_mut() only in debug builds, and is erased in release builds.
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fn tap_borrow_dbg<B>(self, func: impl FnOnce(&B)) -> Self
where Self: Borrow<B>, B: ?Sized,

Calls .tap_borrow() only in debug builds, and is erased in release builds.
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fn tap_borrow_mut_dbg<B>(self, func: impl FnOnce(&mut B)) -> Self
where Self: BorrowMut<B>, B: ?Sized,

Calls .tap_borrow_mut() only in debug builds, and is erased in release builds.
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fn tap_ref_dbg<R>(self, func: impl FnOnce(&R)) -> Self
where Self: AsRef<R>, R: ?Sized,

Calls .tap_ref() only in debug builds, and is erased in release builds.
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fn tap_ref_mut_dbg<R>(self, func: impl FnOnce(&mut R)) -> Self
where Self: AsMut<R>, R: ?Sized,

Calls .tap_ref_mut() only in debug builds, and is erased in release builds.
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fn tap_deref_dbg<T>(self, func: impl FnOnce(&T)) -> Self
where Self: Deref<Target = T>, T: ?Sized,

Calls .tap_deref() only in debug builds, and is erased in release builds.
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fn tap_deref_mut_dbg<T>(self, func: impl FnOnce(&mut T)) -> Self
where Self: DerefMut<Target = T> + Deref, T: ?Sized,

Calls .tap_deref_mut() only in debug builds, and is erased in release builds.
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impl<T> TryConv for T

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fn try_conv<T>(self) -> Result<T, Self::Error>
where Self: TryInto<T>,

Attempts to convert self into T using TryInto<T>. Read more
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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<F, T, E> TryFuture for F
where F: Future<Output = Result<T, E>> + ?Sized,

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type Ok = T

The type of successful values yielded by this future
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type Error = E

The type of failures yielded by this future
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fn try_poll( self: Pin<&mut F>, cx: &mut Context<'_> ) -> Poll<<F as Future>::Output>

Poll this TryFuture as if it were a Future. Read more
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impl<Fut> TryFutureExt for Fut
where Fut: TryFuture + ?Sized,

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fn flatten_sink<Item>(self) -> FlattenSink<Self, Self::Ok>
where Self::Ok: Sink<Item, Error = Self::Error>, Self: Sized,

Available on crate feature sink only.
Flattens the execution of this future when the successful result of this future is a [Sink]. Read more
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fn map_ok<T, F>(self, f: F) -> MapOk<Self, F>
where F: FnOnce(Self::Ok) -> T, Self: Sized,

Maps this future’s success value to a different value. Read more
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fn map_ok_or_else<T, E, F>(self, e: E, f: F) -> MapOkOrElse<Self, F, E>
where F: FnOnce(Self::Ok) -> T, E: FnOnce(Self::Error) -> T, Self: Sized,

Maps this future’s success value to a different value, and permits for error handling resulting in the same type. Read more
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fn map_err<E, F>(self, f: F) -> MapErr<Self, F>
where F: FnOnce(Self::Error) -> E, Self: Sized,

Maps this future’s error value to a different value. Read more
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fn err_into<E>(self) -> ErrInto<Self, E>
where Self: Sized, Self::Error: Into<E>,

Maps this future’s Error to a new error type using the Into trait. Read more
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fn ok_into<U>(self) -> OkInto<Self, U>
where Self: Sized, Self::Ok: Into<U>,

Maps this future’s Ok to a new type using the Into trait.
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fn and_then<Fut, F>(self, f: F) -> AndThen<Self, Fut, F>
where F: FnOnce(Self::Ok) -> Fut, Fut: TryFuture<Error = Self::Error>, Self: Sized,

Executes another future after this one resolves successfully. The success value is passed to a closure to create this subsequent future. Read more
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fn or_else<Fut, F>(self, f: F) -> OrElse<Self, Fut, F>
where F: FnOnce(Self::Error) -> Fut, Fut: TryFuture<Ok = Self::Ok>, Self: Sized,

Executes another future if this one resolves to an error. The error value is passed to a closure to create this subsequent future. Read more
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fn inspect_ok<F>(self, f: F) -> InspectOk<Self, F>
where F: FnOnce(&Self::Ok), Self: Sized,

Do something with the success value of a future before passing it on. Read more
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fn inspect_err<F>(self, f: F) -> InspectErr<Self, F>
where F: FnOnce(&Self::Error), Self: Sized,

Do something with the error value of a future before passing it on. Read more
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fn try_flatten(self) -> TryFlatten<Self, Self::Ok>
where Self::Ok: TryFuture<Error = Self::Error>, Self: Sized,

Flatten the execution of this future when the successful result of this future is another future. Read more
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fn try_flatten_stream(self) -> TryFlattenStream<Self>
where Self::Ok: TryStream<Error = Self::Error>, Self: Sized,

Flatten the execution of this future when the successful result of this future is a stream. Read more
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fn unwrap_or_else<F>(self, f: F) -> UnwrapOrElse<Self, F>
where Self: Sized, F: FnOnce(Self::Error) -> Self::Ok,

Unwraps this future’s output, producing a future with this future’s Ok type as its Output type. Read more
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fn into_future(self) -> IntoFuture<Self>
where Self: Sized,

Wraps a [TryFuture] into a type that implements Future. Read more
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fn try_poll_unpin( &mut self, cx: &mut Context<'_> ) -> Poll<Result<Self::Ok, Self::Error>>
where Self: Unpin,

A convenience method for calling [TryFuture::try_poll] on Unpin future types.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V

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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a [WithDispatch] wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a [WithDispatch] wrapper. Read more