pub struct WeakUnboundedSender<T> { /* private fields */ }
Expand description

An unbounded sender that does not prevent the channel from being closed.

If all UnboundedSender instances of a channel were dropped and only WeakUnboundedSender instances remain, the channel is closed.

In order to send messages, the WeakUnboundedSender needs to be upgraded using WeakUnboundedSender::upgrade, which returns Option<UnboundedSender>. It returns None if all UnboundedSenders have been dropped, and otherwise it returns an UnboundedSender.

#Examples

use tokio::sync::mpsc::unbounded_channel;

#[tokio::main]
async fn main() {
    let (tx, _rx) = unbounded_channel::<i32>();
    let tx_weak = tx.downgrade();
   
    // Upgrading will succeed because `tx` still exists.
    assert!(tx_weak.upgrade().is_some());
   
    // If we drop `tx`, then it will fail.
    drop(tx);
    assert!(tx_weak.clone().upgrade().is_none());
}

Implementations§

Tries to convert a WeakUnboundedSender into an UnboundedSender. This will return Some if there are other Sender instances alive and the channel wasn’t previously dropped, otherwise None is returned.

Trait Implementations§

Returns a copy of the value. Read more
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Auto Trait Implementations§

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TODO: once 1.33.0 is the minimum supported compiler version, remove Any::type_id_compat and use StdAny::type_id instead. https://github.com/rust-lang/rust/issues/27745
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