Module std::time

let five_seconds = Duration::from_secs(5);
assert_eq!(five_seconds, Duration::from_millis(5_000));
assert_eq!(five_seconds, Duration::from_micros(5_000_000));
assert_eq!(five_seconds, Duration::from_nanos(5_000_000_000));

let ten_seconds = Duration::from_secs(10);
let seven_nanos = Duration::from_nanos(7);
let total = ten_seconds + seven_nanos;
assert_eq!(total, Duration::new(10, 7));

let now = Instant::now();

// Calling a slow function, it may take a while
slow_function();

let elapsed_time = now.elapsed();
println!("Running slow_function() took {} seconds.", elapsed_time.as_secs());