socks5代理服务器代码，不依赖环境，支持Ipv4和Ipv6，目前仅能处理socks5中的connect请求，bind和udpassociate请求尚不能处理，使用event通知框架，性能较好(Socks5 proxy code, independent of the environment, supports Ipv4 and Ipv6, can only handle connect requests in Socks5 at the moment, and bind and udpassociate requests are not yet processed, and the event notification framework is better.)