Rust deadlock example with multiple threads

deadlock.rs

// help from https://gist.github.com/wuct/b98f42dba91a8c08cc6ba2d820d94c1c
//
use std::sync::{Arc, Mutex};
use std::thread;

fn acquire_lock(a: Arc<Mutex<i32>>, b: Arc<Mutex<i32>>) {
    // note: if you do the commented out it doesn't deadlock, think about why that is
    // let mut a_num = *a.lock().unwrap();
    // a_num += 1;
    let mut a_num = a.lock().unwrap();
    *a_num += 1;
    let delay = std::time::Duration::from_millis(1000);
    std::thread::sleep(delay);
    // let mut b_num = *b.lock().unwrap();
    // b_num += 1;
    let mut b_num = b.lock().unwrap();
    *b_num += 1;
    println!("{a_num} {b_num}");
}

fn main() {
    let mux1: Arc<Mutex<i32>> = Arc::new(Mutex::new(0));
    let mux2: Arc<Mutex<i32>> = Arc::new(Mutex::new(0));

    let mux1_clone1 = Arc::clone(&mux1);
    let mux2_clone1 = Arc::clone(&mux2);

    let mux1_clone2 = Arc::clone(&mux1);
    let mux2_clone2 = Arc::clone(&mux2);

    let t1 = thread::spawn(move || acquire_lock(mux1_clone1, mux2_clone1));
    let t2 = thread::spawn(move || acquire_lock(mux2_clone2, mux1_clone2));

    let _ = t1.join();
    let _ = t2.join();

    println!("Done {}", *mux1.lock().unwrap()); // never reach here
    println!("Done {}", *mux2.lock().unwrap()); // never reach here

    println!("the end?");
}