use global static variable in rust

main.rs

thread_local!(static data: RefCell<HashMap<String, i32>> = RefCell::new(HashMap::new()));

fn main() {
    let x = || {
        data.with(|c| {
            c.borrow_mut().insert("a".to_string(), 1);
        });
    };

    let y = || {
        data.with(|c| {
            c.borrow_mut().insert("b".to_string(), 2);
        });
    };
    x();
    y();

    data.with(|c| {
        println!("{:?}", c);
    });
}

main2.rs

use std::cell::RefCell;
use std::collections::HashMap;

fn main() {
    let data = RefCell::new(HashMap::new());

    let x = || {
        data.borrow_mut().insert("a".to_string(), 1);
    };

    let y = || {
        data.borrow_mut().insert("b".to_string(), 2);
    };

    x();
    y();

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