code: public boolean isSet(_Fields field) {
      if (field == null) {
        throw new IllegalArgumentException();
      }
  
      switch (field) {
      case START_TOKEN:
        return isSetStart_token();
      case END_TOKEN:
        return isSetEnd_token();
      case ENDPOINTS:
        return isSetEndpoints();
      case RPC_ENDPOINTS:
        return isSetRpc_endpoints();
      case ENDPOINT_DETAILS:
        return isSetEndpoint_details();
      }
      throw new IllegalStateException();
    }
docs: Returns true if field corresponding to fieldID is set (has been assigned a value) and false otherwise