start method

void start()

Implementation

void start() {
  _timer = Timer.periodic(const Duration(seconds: 1), (timer) {
    _countdownSeconds--;
    if (_onTick != null) {
      _onTick(_countdownSeconds);
    }

    if (_countdownSeconds <= 0) {
      stop();
      if (_onFinished != null) {
        _onFinished();
      }
    }
  });
}