Struct Permit

pub struct Permit<'a, T> { /* private fields */ }

Available on crate feature sync only.

Permits to send one value into the channel.

Permit values are returned by Sender::reserve() and Sender::try_reserve() and are used to guarantee channel capacity before generating a message to send.

Implementations

impl<T> Permit<'_, T>

pub fn send(self, value: T)

Sends a value using the reserved capacity.

Capacity for the message has already been reserved. The message is sent to the receiver and the permit is consumed. The operation will succeed even if the receiver half has been closed. See Receiver::close for more details on performing a clean shutdown.

Examples

use tokio::sync::mpsc;

let (tx, mut rx) = mpsc::channel(1);

// Reserve capacity
let permit = tx.reserve().await.unwrap();

// Trying to send directly on the `tx` will fail due to no
// available capacity.
assert!(tx.try_send(123).is_err());

// Send a message on the permit
permit.send(456);

// The value sent on the permit is received
assert_eq!(rx.recv().await.unwrap(), 456);

Trait Implementations

impl<T> Debug for Permit<'_, T>

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

Formats the value using the given formatter. Read more

impl<T> Drop for Permit<'_, T>

fn drop(&mut self)

Executes the destructor for this type. Read more

fn pin_drop(self: Pin<&mut Self>)

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

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned. Read more

Auto Trait Implementations

impl<'a, T> Freeze for Permit<'a, T>

impl<'a, T> RefUnwindSafe for Permit<'a, T>

impl<'a, T> Send for Permit<'a, T>
where T: Send,

impl<'a, T> Sync for Permit<'a, T>
where T: Send,

impl<'a, T> Unpin for Permit<'a, T>

impl<'a, T> UnsafeUnpin for Permit<'a, T>

impl<'a, T> UnwindSafe for Permit<'a, T>

Blanket Implementations

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

fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more

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

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

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

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

Mutably borrows from an owned value. Read more

impl<T> From<T> for T

fn from(t: T) -> T

Returns the argument unchanged.

impl<T> Instrument for T

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

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more

fn in_current_span(self) -> Instrumented<Self> ⓘ

Instruments this type with the current Span, returning an Instrumented wrapper. Read more

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

fn into(self) -> U

Calls U::from(self).

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

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

type Error = Infallible

The type returned in the event of a conversion error.

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

Performs the conversion.

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

type Error = >::Error

The type returned in the event of a conversion error.

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

Performs the conversion.

impl<T> WithSubscriber for T

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

fn with_current_subscriber(self) -> WithDispatch<Self> ⓘ

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