code: public boolean isSet(_Fields field) {
      if (field == null) {
        throw new IllegalArgumentException();
      }
  
      switch (field) {
      case HOST:
        return is_set_host();
      case SUPERVISOR_ID:
        return is_set_supervisorId();
      case UPTIME_SECS:
        return is_set_uptimeSecs();
      case NUM_WORKERS:
        return is_set_numWorkers();
      case NUM_USED_WORKERS:
        return is_set_numUsedWorkers();
      case VERSION:
        return is_set_version();
      case BUILD_TS:
        return is_set_buildTs();
      case PORT:
        return is_set_port();
      case ERROR_MESSAGE:
        return is_set_errorMessage();
      }
      throw new IllegalStateException();
    }
docs: Returns true if field corresponding to fieldID is set (has been assigned a value) and false otherwise