subtractTime method
Subtract time from the current timer
Implementation
void subtractTime(Duration timeToSubtract) {
if (timeToSubtract.isNegative) {
_setError('Cannot subtract negative time');
return;
}
if (_remaining > timeToSubtract) {
_remaining = _remaining - timeToSubtract;
_totalDuration = _totalDuration - timeToSubtract;
} else {
_remaining = Duration.zero;
_finishTimer();
}
notifyListeners();
}