t.Errorf("got body %q; expected %q", bodyBytes, expected)
	}
	if !mf.flushed {
		t.Errorf("response writer was not flushed")
	}
}

func TestReverseProxyFlushIntervalHeaders(t *testing.T) {
	const expected = "hi"
	stopCh := make(chan struct{})
	backend := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Add("MyHeader", expected)