if err != nil {
		t.Fatalf("Dial: %v", err)
	}
	defer c.Close()
	if _, err := io.WriteString(c, "GET / HTTP/1.1\r\nHost: foo\r\n\r\n"); err != nil {
		t.Fatal(err)
	}
	bs := bufio.NewScanner(c)
	var got strings.Builder
	for bs.Scan() {
		if strings.TrimSpace(bs.Text()) == "" {
			break
		}
		got.WriteString(bs.Text())
		got.WriteByte('\n')
	}
	if err := bs.Err(); err != nil {

			t.Error(err)
			return
		}
		defer conn.Close()
		io.WriteString(conn, "HTTP/1.1 101 Switching Protocols Hi\r\nConnection: upgRADe\r\nUpgrade: foo\r\n\r\nSome buffered data\n")
		bs := bufio.NewScanner(conn)
		bs.Scan()
		fmt.Fprintf(conn, "%s\n", strings.ToUpper(bs.Text()))
		<-done
	}))

	req, _ := NewRequest("GET", cst.ts.URL, nil)
	req.Header.Set("Upgrade", "foo")