public WebSocketManagerMiddleware(RequestDelegate next,
                                   WebSocketHandler webSocketHandler)
 {
     _next             = next;
     _webSocketHandler = webSocketHandler;
 }
 /// <summary>
 /// 指定ws路径对应的服务
 /// </summary>
 /// <param name="app"></param>
 /// <param name="path"></param>
 /// <param name="handler"></param>
 /// <returns></returns>
 public static IApplicationBuilder MapWebSocketManager(this IApplicationBuilder app,
                                                       PathString path,
                                                       WebSocketHandler handler)
 {
     return(app.Map(path, (_app) => _app.UseMiddleware <WebSocketManagerMiddleware>(handler)));
 }