docs: private Runnable shutdownAfterHandoff(final String workUnit)
      {
          final Cluster cluster = this.cluster;
          final Logger log = LOG;
          return new Runnable() {
              @Override
              public void run() {
                  String str = cluster.getHandoffResult(workUnit);
                  log.info("Shutting down {} following handoff to {}.",
                          workUnit, (str == null) ? "(None)" : str);
                  cluster.shutdownWork(workUnit, /*doLog =*/ false);
  
                  if (cluster.hasState(NodeState.Draining) && cluster.myWorkUnits.isEmpty()) {
                      cluster.shutdown();
                  }
              }
          };
      }