@Override
                public void onNext(@NonNull final GeoData value) {
                    emitter.onNext(value);
                }
Encapsulates Google's location services, especially its FusedLocationProvider,
as described here: <a href="https://developers.google.com/location-context/fused-location-provider">...</a>
main/src/main/java/cgeo/geocaching/playservices/GoogleLocationProvider.java