cst := newClientServerTest(t, mode, HandlerFunc(func(w ResponseWriter, r *Request) {
		w.Header().Set("Foo", "Bar")
		w.Header().Set("Trailer:Foo", "Baz")
		w.(Flusher).Flush()
		w.Header().Add("Trailer:Foo", "Baz2")
		w.Header().Set("Trailer:Bar", "Quux")
	}))
	res, err := cst.c.Get(cst.ts.URL)
	if err != nil {
		t.Fatal(err)
	}
	if _, err := io.Copy(io.Discard, res.Body); err != nil {
		t.Fatal(err)
	}