code: private boolean isSwitcherChange(boolean switcherStatus) {
  		boolean ret = false;
  		if (switcherStatus != lastHeartBeatSwitcherStatus) {
  			ret = true;
  			lastHeartBeatSwitcherStatus = switcherStatus;
  			logger.info("heartbeat switcher change to " + switcherStatus);
  		}
  		return ret;
  	}
docs: check heart beat switcher status, if switcher is changed, then change lastHeartBeatSwitcherStatus
  to the latest status.
  
  @param switcherStatus
  @return