code: public boolean addWaitingWork(final T context) {
  	write.lock();
  	try {
  	    boolean result = !waitingWork.contains(context);
  	    if (result) {
  		waitingWork.add(context);
  		workChanged.signalAll(); // Wake up!
  	    }
  	    return result;
  	} finally {
  	    write.unlock();
  	}
      }
docs: Adds work to the queue.
  
  @param context
  Work to add.
  @return Whether the work was not previously within the queue.