code: public boolean isSet(_Fields field) {
      if (field == null) {
        throw new IllegalArgumentException();
      }
  
      switch (field) {
      case TOPOLOGY_METRIC:
        return is_set_topologyMetric();
      case COMPONENT_METRIC:
        return is_set_componentMetric();
      case WORKER_METRIC:
        return is_set_workerMetric();
      case TASK_METRIC:
        return is_set_taskMetric();
      case STREAM_METRIC:
        return is_set_streamMetric();
      case NETTY_METRIC:
        return is_set_nettyMetric();
      case COMP_STREAM_METRIC:
        return is_set_compStreamMetric();
      }
      throw new IllegalStateException();
    }
docs: Returns true if field corresponding to fieldID is set (has been assigned a value) and false otherwise