C#下如何实现Server-Sent Event(SSE)

class SSEServer {
    private static HttpListener listener;

    public bool Start() {
        try {
            listener = new HttpListener();
            listener.Prefixes.Add($ "http://+:{Properties.Settings.Default.ServerPort}/");  // 监听配置文件中的IP地址，必须以`/`结尾
            listener.Start();
            listener.BeginGetContext(GetContentCallBack, listener); //当创建连接后响应的函数
        } catch (Exception ex) {
            MessageBox.Show("创建服务异常,请检查端口是否被占用：\n" + ex);
            return false;
        }
        return true;
    }

    public void Stop() {
        if (listener.IsListening) {
            listener.Stop();
        }
    }

    private void GetContentCallBack(IAsyncResult ar) {

        HttpListener _listener = ar.AsyncState as HttpListener; //异步服务，避免阻塞，也能接收多条连接
        if (_listener.IsListening) {
            HttpListenerContext context = _listener.EndGetContext(ar);
            _listener.BeginGetContext(new AsyncCallback(GetContentCallBack), _listener); // 创建新线程监听其他请求

            HttpListenerRequest req = context.Request; //获取连接请求体
            if (req.HttpMethod == "GET") //SSE只接受GET请求
            {
                HttpListenerResponse response = context.Response; //获取连接响应体
                response.StatusCode = (int) HttpStatusCode.OK; //设定状态码
                response.ContentType = "text/event-stream;charset=UTF-8"; //设定SSE的响应头
                response.AddHeader("Cache-Control", "no-cache");
                response.AddHeader("Connection", "keep-alive");
                response.AddHeader("Access-Control-Allow-Origin", "*");
                response.AddHeader("Transfer-Encoding", "chunked");
                response.ContentEncoding = Encoding.UTF8; //各种各样的响应头
                using(var stream = response.OutputStream) { //创建响应体自带的缓存流
                    while (true) {
                        try {
                            var data = Encoding.UTF8.GetBytes($ "Event: message\ndata: Hello World！\n\n"); //必须以UTF8编码发送数据
                            stream.Write(data, 0, data.Length);
                            Thread.Sleep(1000); //一秒发送一次数据
                        } catch { //有问题直接catch
                                }));
                            }
                            _listener.Close(); //关闭当前线程的连接
                            break; //当前连接响应函数运行完毕
                        }
                    }
                }
            }
        }
    }