code: protected void post(Runnable runnable) {
          Ln.d("Message queue is " + messageQueue);
  
          if (messageQueue == null) {
              return;
          }
          messageQueue.postAtTime(runnable, SystemClock.uptimeMillis());
      }
docs: Add the request update to the observer message queue.
  @param runnable a runnable to be posted immediatly on the queue.