use std::sync::mpsc::sync_channel;
use std::thread;

// Create a rendezvous sync_channel with buffer size 0
let (sync_sender, receiver) = sync_channel(0);

thread::spawn(move || {
   println!("sending message...");
   sync_sender.send(1).unwrap();
   // Thread is now blocked until the message is received

   println!("...message received!");
});

let msg = receiver.recv().unwrap();
assert_eq!(1, msg);

use std::sync::mpsc::sync_channel;
use std::thread;

// Create a sync_channel with buffer size 1
let (sync_sender, receiver) = sync_channel(1);
let sync_sender2 = sync_sender.clone();

// First thread owns sync_sender
thread::spawn(move || {
    sync_sender.send(1).unwrap();
    sync_sender.send(2).unwrap();
    // Thread blocked
});

// Second thread owns sync_sender2
thread::spawn(move || {
    // This will return an error and send
    // no message if the buffer is full
    let _ = sync_sender2.try_send(3);
});

let mut msg;
msg = receiver.recv().unwrap();
println!("message {} received", msg);

msg = receiver.recv().unwrap();
println!("message {} received", msg);

// Third message may have never been sent
match receiver.try_recv() {
    Ok(msg) => println!("message {} received", msg),
    Err(_) => println!("the third message was never sent"),
}