Channel Enums

Channel-related enums สำหรับ inter-thread communication ใน Rust รวมถึง error types สำหรับ send และ receive operations

1. TryRecvError

Error type สำหรับ non-blocking receive operations

Handling TryRecvError

use std::sync::mpsc::{channel, TryRecvError};
use std::thread;
use std::time::Duration;

fn main() {
    let (tx, rx) = channel();

    // TryRecvError::Empty - channel empty but senders exist
    match rx.try_recv() {
        Ok(msg) => println!("Got: {}", msg),
        Err(TryRecvError::Empty) => println!("Channel empty, sender alive"),
        Err(TryRecvError::Disconnected) => println!("Sender gone"),
    }

    // Spawn sender
    let handle = thread::spawn(move || {
        thread::sleep(Duration::from_millis(100));
        tx.send("Hello").unwrap();
    });

    // Polling pattern
    loop {
        match rx.try_recv() {
            Ok(msg) => {
                println!("Received: {}", msg);
                break;
            }
            Err(TryRecvError::Empty) => {
                println!("Waiting...");
                thread::sleep(Duration::from_millis(50));
            }
            Err(TryRecvError::Disconnected) => {
                println!("Sender disconnected");
                break;
            }
        }
    }

    handle.join().unwrap();
}