Tokio delayed queue

Asynchronous delayed queue for Tokio runtime.

Features

• multi-consume
• multi-produce
• fixed queue size
• atomic pop with pop-future cancelation

Example

let queue = DelayedQueue::new_bound(NonZeroUsize::new(16).unwrap());

// Push
queue.push(1, Duration::from_secs(1)).await;
queue.push(1, Duration::from_secs(2)).await;

// Pop
let v = queue.pop().await;
assert_eq!(v, 1);

// Other future
let join = tokio::spawn({
    let queue = queue.clone();
    async move {
        // Cancelled 1
        let dropped_future = queue.pop();
        drop(dropped_future);

        // Cancelled 2
        let dropped_future = queue.pop();
        drop(dropped_future);

        // Pop
        let v = queue.pop().await;
        assert_eq!(v, 1);

        // Pop
        let v = queue.pop().await;
        assert_eq!(v, 1);
    }
});

// Push
queue.push(1, Duration::from_secs(2)).await;

join.await.unwrap();