code: public static void setFlatfile(Set<H2ONode> nodes) {
      if (nodes == null) {
        STATIC_H2OS = null;
      } else {
        STATIC_H2OS = Collections.newSetFromMap(new ConcurrentHashMap<H2ONode, Boolean>());
        STATIC_H2OS.addAll(nodes);
      }
    }
docs: Setup a set of nodes which should be contacted during manual multicast
  
  @param nodes set of H2O nodes