code: public Future<?> asynchronouslyDetermineLocalReplicas() {
          return VoltDB.instance().getSES(false).submit(new Runnable() {
  
              @Override
              public void run() {
                  /*
                   * Assemble a map of all local replicas that will be used to determine
                   * if single part reads can be delivered and executed at local replicas
                   */
                  final int thisHostId = CoreUtils.getHostIdFromHSId(m_mailbox.getHSId());
                  ImmutableMap.Builder<Integer, Long> localReplicas = ImmutableMap.builder();
                  for (int partition : m_cartographer.getPartitions()) {
                      for (Long replica : m_cartographer.getReplicasForPartition(partition)) {
                          if (CoreUtils.getHostIdFromHSId(replica) == thisHostId) {
                              localReplicas.put(partition, replica);
                          }
                      }
                  }
                  m_localReplicas.set(localReplicas.build());
              }
  
          });
      }
docs: /*
  This does a ZK lookup which apparently is full of fail
  if you run TestRejoinEndToEnd. Kind of lame, but initializing this data
  immediately is not critical, request routing works without it.
  
  Populate the map in the background and it will be used to route
  requests to local replicas once the info is available