log.Fatal(err)
	}
	greeting, err := io.ReadAll(res.Body)
	res.Body.Close()
	if err != nil {
		log.Fatal(err)
	}

	fmt.Printf("%s", greeting)
	// Output: Hello, client
}

func ExampleServer_hTTP2() {
	ts := httptest.NewUnstartedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprintf(w, "Hello, %s", r.Proto)
	}))
	ts.EnableHTTP2 = true
	ts.StartTLS()
	defer ts.Close()