Function clear_user_message

src/brpc/socket.cpp:349–351

        return _pc_and_udmsg.get();
    }
    void clear_user_message() {
        _pc_and_udmsg.reset();
    }
    void set_pipelined_count_and_user_message(
        uint32_t pc, SocketMessage* msg, uint32_t auth_flags) {
        if (auth_flags) {