说明：  本程序采用tcp/ip socket多线程编程，并对一些重要的同步操作做了超时控制，以减少等待的时间，像连接服务器，等待对方接收文件等。基本功能跟QQ类似，能进行多点的聊天和点对点的文件传送。
(This procedure using tcp/ip socket multi-threaded programming, a number of important and did a time-out synchronization control, in order to reduce the waiting time, such as connect to a server, waiting for the other party to receive documents. QQ with the basic functions similar to multi-point chat and peer-to-peer file transfer.)