New rule for detecting if an emitter is disposed before emitting

[juliocbcotta]

Hey, would it be possible to have a new rule that checks if emitter.isDIsposed() is called before publishing an update?
For cases like below:

Maybe.create((MaybeOnSubscribe<LatLng>) emitter -> {
               LatLng coordinates = null;
               try {
                   coordinates = computeCoordinates();
                  if (!emitter.isDisposed()) {
                        if (coordinates != null) {
                            emitter.onSuccess(coordinates);
                        } else {
                            emitter.onComplete();
                        }
                    }
                  } catch (final Exception e) {
                    if (!emitter.isDisposed()) {
                         emitter.onError(e);
                    }
            }

It seems that without the check we can get non deliverable exceptions.
Thanks

[hvisser]

Should be possible for sure, though as always it could be a bit tricky to check. I'm open to contributions if anyone wants to give this a try.