2 Checks for `mem::replace()` on an `Option` with
6 `Option` already has the method `take()` for
7 taking its current value (Some(..) or None) and replacing it with
14 let mut an_option = Some(0);
15 let replaced = mem::replace(&mut an_option, None);
17 Is better expressed with:
19 let mut an_option = Some(0);
20 let taken = an_option.take();