code: public void locateGroup(String cluster, String group, Handler<AsyncResult<String>> doneHandler) {
      locateGroup(String.format("%s.%s", cluster, group), doneHandler);
    }
docs: Locates the local address of the nearest group node if one exists.
  
  @param cluster The cluster in which to search for the node.
  @param group The group to search.
  @param doneHandler A handler to be called once the address has been located.