receive_1.rs

// Note select is unstable,
// consider using crossbeam-channel instead...
#![feature(mpsc_select)]

loop {
    let msg = {
        let sel = Select::new();
        // Selecting over our "work receiver",
        // corresponding to the sender shared with the "producer"
        // And our "results receiver", corresponding
        // with the sender shared with the "consumer".
        // So we're either getting work, or results.
        let mut work_port = sel.handle(&work_receiver);
        let mut results_port = sel.handle(&results_receiver);
        unsafe {
            work_port.add();
            results_port.add();
        }
        let ready = sel.wait(); 
        if ready == work_port.id() {
            MainMsg::FromProducer(work_port.recv().unwrap())
        } else if ready == results_port.id() {
            MainMsg::FromConsumer(results_port.recv().unwrap())
        } else {
            panic!("unexpected select result")
        }
    };
    // Handling the "msg" below...
}