docs: private void handleTMasterLocationRefreshMessage(
        Metrics.MetricPublisher request,
        Metrics.TMasterLocationRefreshMessage tMasterLocationRefreshMessage) {
      TopologyMaster.TMasterLocation oldLocation =
          (TopologyMaster.TMasterLocation)
              SingletonRegistry.INSTANCE.getSingleton(TMASTER_LOCATION_BEAN_NAME);
  
      TopologyMaster.TMasterLocation newLocation = tMasterLocationRefreshMessage.getTmaster();
  
      if (oldLocation == null) {
        // The first time to get TMasterLocation
  
        // Register to the SingletonRegistry
        LOG.info("We received a new TMasterLocation. Register it into SingletonRegistry");
        SingletonRegistry.INSTANCE.registerSingleton(TMASTER_LOCATION_BEAN_NAME, newLocation);
  
        // Update Metrics
        serverMetricsCounters.scope(SERVER_NEW_TMASTER_LOCATION).incr();
  
      } else if (oldLocation.equals(newLocation)) {
        // The new one is the same as old one.
  
        // Just Log. Do nothing
        LOG.info("We received a new TMasterLocation the same as the old one. Do nothing.");
      } else {
        // Have received TMasterLocation earlier, but it changed.
  
        // We need update the SingletonRegistry
        LOG.info("We received a new TMasterLocation. Replace the old one.");
        LOG.info("Old TMasterLocation: " + oldLocation);
        SingletonRegistry.INSTANCE.updateSingleton(TMASTER_LOCATION_BEAN_NAME, newLocation);
  
        // Update Metrics
        serverMetricsCounters.scope(SERVER_NEW_TMASTER_LOCATION).incr();
      }
  
      LOG.info("Current TMaster location: " + newLocation);
  
      // Update Metrics
      serverMetricsCounters.scope(SERVER_TMASTER_LOCATION_RECEIVED).incr();
    }