How do I switch off a watcher - watchasync (RealmEventStreamAsyncTask)?

I have set up a watcher in android with java. It works, but I would like to switch it off when I leave the fragment but I don’t know how to do that.

private RealmEventStreamAsyncTask<RealmLogEntry> watcher;

 watcher = mongoDBcollection.watchAsync();
        watcher.get(resultWatch -> {
            if (resultWatch.isSuccess()) {
                Log.v(TAG, "Event type: " +
                        resultWatch.get().getOperationType() + " full document: " +
            } else {
                Log.e(TAG, "failed to subscribe to changes in the collection with : ",

I think I would have to switch it off in the onDestroy method, but how?

    public void onDestroyView() {