public static <T> Observable<T> bindActivity(final Activity activity, final Observable<T> source) {
        final WeakReference<Activity> activityRef = new WeakReference<>(activity);
        return source.observeOn(AndroidSchedulers.mainThread()).takeWhile(t -> {
            final Activity a = activityRef.get();
            return a != null && !a.isFinishing();
        });
    }
This Scheduler is intended for queuing Geocache refreshes.
<br>
Don't use it for anything else than that.
It shall SOLELY be used by {@link cgeo.geocaching.CacheDetailActivity} and {@link cgeo.geocaching.service.CacheDownloaderService}!
main/src/main/java/cgeo/geocaching/utils/AndroidRxUtils.java