docs: void heartbeat() {
          if (!clusterService.isJoined()) {
              return;
          }
  
          checkClockDrift(heartbeatIntervalMillis);
  
          final long clusterTime = clusterClock.getClusterTime();
          if (clusterService.isMaster()) {
              heartbeatWhenMaster(clusterTime);
          } else {
              heartbeatWhenSlave(clusterTime);
          }
      }