code: private Node scanTerritory(DistanceMap map, String desired, String supported) {
      Node node;
      for (String partition : PARTITION_TABLE.getRegionPartition(desired)) {
        node = map.get(partition, supported);
        if (node != null) {
          return node;
        }
      }
      
      for (String partition : PARTITION_TABLE.getRegionPartition(supported)) {
        node = map.get(desired, partition);
        if (node != null) {
          return node;
        }
      }
      
      return null;
    }
docs: Scan the desired region against the supported partitions and vice versa.
  Return the first matching node.