I've just started learning about @ngrx/store and @ngrx.effects and have created my first effect in my Angular/Ionic app. It runs ok the first time but if I dispatch the event to the store again (i.e when clicking the button again), nothing happens (no network call is made, nothing in console logs). Is there something obvious I'm doing wrong? Here's the effect:

```
@Effect() event_response$ = this.action$
    .ofType(SEND_EVENT_RESPONSE_ACTION)
    .map(toPayload)
    .switchMap((payload) => this.myService.eventResponse(payload.eventId,payload.response))
    .map(data => new SentEventResponseAction(data))
    .catch((error) => Observable.of(new ErrorOccurredAction(error)));

```

Thanks