use std::sync::{Arc, Mutex};
use std::thread;

fn main() {
    let data = Arc::new(Mutex::new(vec![1, 2, 3]));
    let mut handlers = vec![];

    for i in 0..3 {
        let data = data.clone();
        handlers.push(thread::spawn(move || {
            let mut data = data.lock().unwrap();
            data[0] += i;
        }));
    }
    for each in handlers {
        each.join().unwrap();
    }

    println!("{:?}", data);
}