public class BackgroundHandler : IHttpHandler
    {

        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";

            var hub = GlobalHost.ConnectionManager.GetHubContext<HubDemo>();
            //在集线器外部推送消息
            hub.Clients.All.notice("都起来吃饭了");
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }