@Subscribe
    public void listenForStrings(String event) {
      eventsReceived.add(event);
      ready = false;
      try {
        bus.post(SECOND);
      } finally {
        ready = true;
      }
    }
Validate that {@link Bus} behaves carefully when listeners publish
their own events.

@author Jesse Wilson
otto/src/test/java/com/squareup/otto/ReentrantEventsTest.java