grpc_session_attr_destruct_np - Destructs session attributes.
  grpc_error_t grpc_session_attr_destruct_np(grpc_session_attr_t_np *attr)
  grpc_session_attr_t_np *attrThe grpc_session_attr_destruct_np() function destructs session attributes.
This function is MT-safe.
If successful, GRPC_NO_ERROR is returned. In the case of an error, Error code is returned.
  GRPC_NOT_INITIALIZED  GRPC_OTHER_ERROR_CODE