code: protected Map<String,Map<String,Object>> dumpAttrsSelectedProtocol(String protocol_name, List<String> attrs) {
          return ch.dumpStats(protocol_name, attrs);
      }
docs: Dumps attributes and their values of a given protocol.
  @param protocol_name The name of the protocol
  @param attrs A list of attributes that need to be returned. If null, all attributes of the given protocol will
  be returned
  @return A map of protocol names as keys and maps (of attribute names and values) as values