// Don't always call NewWriter, as that forces a bytes.Buffer
	// and other small bufio Writers to have a minimum 4k buffer
	// size.
	var bw *bufio.Writer
	if _, ok := w.(io.ByteWriter); !ok {
		bw = bufio.NewWriter(w)
		w = bw
	}

	_, err = fmt.Fprintf(w, "%s %s HTTP/1.1\r\n", valueOrDefault(r.Method, "GET"), ruri)
	if err != nil {
		return err
	}

	// Header lines

		{"(*SectionReader).ReadAt", Method, 0},
		{"(*SectionReader).Seek", Method, 0},
		{"(*SectionReader).Size", Method, 0},
		{"ByteReader", Type, 0},
		{"ByteScanner", Type, 0},
		{"ByteWriter", Type, 1},
		{"Closer", Type, 0},
		{"Copy", Func, 0},
		{"CopyBuffer", Func, 5},
		{"CopyN", Func, 0},
		{"Discard", Var, 16},
		{"EOF", Var, 0},
		{"ErrClosedPipe", Var, 0},