📨 Message Passing

Push every item through a channel, then drain the receiver into a Vec (in send order).

`items`	result
`vec![1, 2, 3]`	`[1, 2, 3]`
`vec![]`	`[]`
`vec![42]`	`[42]`

mpsc::channel() returns the pair (Sender<T>, Receiver<T>). tx.send(x) queues a value and the receiver yields values back in send order.

The receiver's iterator ends only when the last sender is dropped. Nothing else holds one here, so drop(tx) before rx.iter().collect() — otherwise it blocks forever waiting on a message that will never come.

Rust

/// Create a channel, send every value from `items` through it, then collect
/// everything the receiver yields into a Vec (in send order).
fn round_trip(items: Vec<i32>) -> Vec<i32> {
    let (tx, rx) = mpsc::channel();
    for x in items {
        tx.send(x).unwrap();
    }
    drop(tx);
    rx.iter().collect()
}

Send and Receive

Worker to Main