result = mBotsRunnerListeners.add(listener);
HashSet clone = (HashSet)mBotsRunnerListeners.clone(); result = clone.add(listener); mBotsRunnerListeners = clone;
	public boolean addBotsRunnerListener(BotsRunnerListener listener)	{		if (null == listener)	throw new IllegalArgumentException("listener can't be null.");		boolean result = false;				synchronized (mBotsRunnerListenersMonitor)		{			if (!mBotsRunnerListeners.contains(listener))			{				result = mBotsRunnerListeners.add(listener);			}			else			{				result = true;			}		}				assert true == mBotsRunnerListeners.contains(listener);				return result;	}