基于完成例程的重叠IO模型，服务器端用个三个辅助线程来处理重叠IO操作，可通过增加线程来提高响应请求速度，此模型比基于事件通知伸缩性更好，服务器端用队列（选择队列更易于管理）存储了某个时间点的客户端socket，再用辅助线程处理-IO overlapped completion routines based model of the server with a three worker threads to handle overlapped IO operation can be improv