fn main() {
    let mut found = None;
    'outer: for i in 0..5 {
        for j in 0..5 {
            if i * j == 6 {
                found = Some((i, j));
                // exit both loops
                break 'outer;
            }
        }
    }
    println!("{:?}", found);
}

break an outer loop by label