code: public void queueNotification (ObserverList.ObserverOp<Object> amop)
      {
          if (_observers != null) {
              if (_mgr != null) {
                  _mgr.queueNotification(_observers, amop);
              } else {
                  log.warning("Have no manager, dropping notification", "media", this, "op", amop);
              }
          }
      }
docs: Queues the supplied notification up to be dispatched to this abstract media's observers.