onStart method
Callback when this executor is started. Returns true if successfully started, false otherwise.
Implementation
@override
Future<bool> onStart() async {
Duration delay = configuration!.firstOccurrence.difference(DateTime.now());
if (configuration!.end == null ||
configuration!.end!.isAfter(DateTime.now())) {
timer = Timer(delay, () async => onTrigger());
}
return true;
}