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 udpass