Observable<dynamic> _simulationStartEpic(
    Stream<dynamic> actions, EpicStore<AppState> epicStore) {
  return Observable(actions)
      .ofType(TypeToken<SimulationStateChangedAction>())
      .doOnData((action) {
    _simulationStateSubject.add(action.simulationState);
  }).switchMap((SimulationStateChangedAction action) {
    if (action.simulationState == SimulationState.ENABLED) {
      return _debouncedSummary()
          .takeUntil(_simulationStateSubject.takeWhile(
              (currentState) => currentState == SimulationState.DISABLED))
          .map((summary) => AddEntryAction(summary));
    } else {
      return Observable.empty();
    }
  });
}