The value was "closing", but by the time drain_requests wakes and checks, it's already "closed". The intermediate state is gone.
ArgUintVar consumes the argument and stores the parsed value in the variable，更多细节参见服务器推荐
Credit: Stan Schroeder/Mashable，这一点在下载安装汽水音乐中也有详细论述
- SET_ERR("Unknown frame number for capture result: %d",