execute method

@override void execute(Observer<T> observer, [ Params? params ])

Executes the usecase on a different isolate. Spawns _isolate using the static method provided by buildUseCaseTask and listens to a BehaviorSubject using the observer provided by the user. All Params are sent to the _isolate through BackgroundUseCaseParams.

Implementation

@override
void execute(Observer<T> observer, [Params? params]) async {
  if (!isRunning) {
    _state = BackgroundUseCaseState.loading;
    _subject.listen(observer.onNext,
        onError: observer.onError, onDone: observer.onComplete);
    _run = buildUseCaseTask();
    Isolate.spawn<BackgroundUseCaseParams>(_run,
            BackgroundUseCaseParams(_receivePort.sendPort, params: params))
        .then<void>((Isolate isolate) {
      if (!isRunning) {
        logger.info('Killing background isolate.');
        isolate.kill(priority: Isolate.immediate);
      } else {
        _state = BackgroundUseCaseState.calculating;
        _isolate = isolate;
      }
    });
  }
}