# DelayQueue for Rust
A concurrent unbounded blocking queue where each element can only be removed when its delay expires.
## Example
```rust
extern crate delay_queue;
use std::time::{Duration, Instant};
use std::thread;
use delay_queue::{Delay, DelayQueue};
fn main() {
let queue: DelayQueue<Delay<&str>> = DelayQueue::new();
// Clone the queue and move it to the consumer thread
let mut consumer_queue = queue.clone();
let consumer_handle = thread::spawn(move || {
// The pop() will block until an item is available and its delay has expired
println!("First pop: {}", consumer_queue.pop().value);
println!("Second pop: {}", consumer_queue.pop().value);
});
// Clone the queue and move it to the producer thread
let mut producer_queue = queue.clone();
let producer_handle = thread::spawn(move || {
// This item can only be popped after 3 seconds have passed
producer_queue.push(Delay::for_duration("3s", Duration::from_secs(3)));
// This item can be popped immediately
producer_queue.push(Delay::until_instant("1s", Instant::now()));
});
consumer_handle.join().unwrap();
producer_handle.join().unwrap();
assert!(queue.is_empty());
}
```
You can run this example with the command `cargo run --example basic_usage`
## License
Licensed under either of
* Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
* MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
at your option.
### Contribution
Unless you explicitly state otherwise, any contribution intentionally
submitted for inclusion in the work by you, as defined in the Apache-2.0
license, shall be dual licensed as above, without any additional terms or
conditions.