func runBackendInstance(ln net.Listener, handler connHandler) {
	var tempDelay time.Duration // how long to sleep on accept failure
	for {
		conn, err := ln.Accept()
		if err != nil {
			if ne, ok := err.(net.Error); ok && ne.Temporary() {
				if tempDelay == 0 {
					tempDelay = 5 * time.Millisecond
				} else {
					tempDelay *= 2
				}
				if max := 1 * time.Second; tempDelay > max {
					tempDelay = max
				}
				fmt.Printf("http: Accept error: %v; retrying in %v\n", err, tempDelay)
				time.Sleep(tempDelay)
				continue
			}
			break
		}
		go func() {
			defer GinkgoRecover()
			handler(test_util.NewHttpConn(conn))
		}()
	}
}

func NewWebSocketApp(urls []route.Uri, rPort uint16, mbusClient yagnats.ApceraWrapperNATSClient, delay time.Duration) *TestApp {
	app := NewTestApp(urls, rPort, mbusClient, nil)
	app.AddHandler("/", func(w http.ResponseWriter, r *http.Request) {
		defer ginkgo.GinkgoRecover()

		Ω(r.Header.Get("Upgrade")).Should(Equal("websocket"))
		Ω(r.Header.Get("Connection")).Should(Equal("upgrade"))

		conn, _, err := w.(http.Hijacker).Hijack()
		x := test_util.NewHttpConn(conn)

		resp := test_util.NewResponse(http.StatusSwitchingProtocols)
		resp.Header.Set("Upgrade", "websocket")
		resp.Header.Set("Connection", "upgrade")

		time.Sleep(delay)

		x.WriteResponse(resp)
		Ω(err).ShouldNot(HaveOccurred())

		x.CheckLine("hello from client")
		x.WriteLine("hello from server")
	})

	return app
}

func registerHandlerWithInstanceId(r *registry.RouteRegistry, u string, h connHandler, instanceId string) net.Listener {
	ln, err := net.Listen("tcp", "127.0.0.1:0")
	Ω(err).NotTo(HaveOccurred())

	go func() {
		var tempDelay time.Duration // how long to sleep on accept failure
		for {
			conn, err := ln.Accept()
			if err != nil {
				if ne, ok := err.(net.Error); ok && ne.Temporary() {
					if tempDelay == 0 {
						tempDelay = 5 * time.Millisecond
					} else {
						tempDelay *= 2
					}
					if max := 1 * time.Second; tempDelay > max {
						tempDelay = max
					}
					fmt.Printf("http: Accept error: %v; retrying in %v\n", err, tempDelay)
					time.Sleep(tempDelay)
					continue
				}
				break
			}
			go func() {
				defer GinkgoRecover()
				h(test_util.NewHttpConn(conn))
			}()
		}
	}()

	registerAddr(r, u, ln.Addr(), instanceId)

	return ln
}

func dialProxy(proxyServer net.Listener) *test_util.HttpConn {
	conn, err := net.Dial("tcp", proxyServer.Addr().String())
	Expect(err).NotTo(HaveOccurred())

	return test_util.NewHttpConn(conn)
}

			w.WriteHeader(http.StatusOK)
			done <- r.Header.Get(router_http.VcapRequestIdHeader)
		})

		app.Listen()
		go app.RegisterRepeatedly(1 * time.Second)

		Eventually(func() bool {
			return appRegistered(registry, app)
		}).Should(BeTrue())

		conn, err := net.Dial("tcp", fmt.Sprintf("%s:%d", config.Ip, config.Port))
		Expect(err).NotTo(HaveOccurred())
		defer conn.Close()

		httpConn := test_util.NewHttpConn(conn)

		req := test_util.NewRequest("GET", "foo.vcap.me", "/", nil)
		req.Header.Add(router_http.VcapRequestIdHeader, "A-BOGUS-REQUEST-ID")

		httpConn.WriteRequest(req)

		var answer string
		Eventually(done).Should(Receive(&answer))
		Expect(answer).ToNot(Equal("A-BOGUS-REQUEST-ID"))
		Expect(answer).To(MatchRegexp(uuid_regex))
		Expect(logger).To(gbytes.Say("vcap-request-id-header-set"))

		resp, _ := httpConn.ReadResponse()
		Expect(resp.StatusCode).To(Equal(http.StatusOK))
	})