How can you properly implement debounced asynchronous validation for a specific field, such as checking username availability against a server, without triggering a genuinely brand new separate network request on essentially every single individual keystroke a user actually types?

Implementing genuinely efficient debounced asynchronous validation means deliberately waiting for a genuinely short, deliberate pause in a user's actual typing before actually triggering a real network request to properly verify something like username availability, rather than wastefully firing off an entirely brand new separate request on essentially every single individual keystroke, and this typically involves using a Timer that gets properly cancelled and restarted from scratch every single time the field's own text actually changes, only genuinely allowing the actual real validation request to finally proceed once that specific timer has genuinely fully elapsed without any further additional interruption.

Timer? _debounce;

void onChanged(String value) {
  _debounce?.cancel();
  _debounce = Timer(Duration(milliseconds: 500), () => checkUsernameAvailability(value));
}