result = mResponseListeners.remove(listener);
HashSet clone = (HashSet)mResponseListeners.clone(); result = clone.remove(listener); mResponseListeners = clone;
	public boolean removeResponseListener(ResponseListener listener)	{		if (null == listener)	throw new IllegalArgumentException("listener can't be null.");        boolean result = false;				synchronized (mResponseListenersMonitor)		{			result = mResponseListeners.remove(listener);		}				assert false == mResponseListeners.contains(listener);				return result;	}