wantTrailers := make(map[string]struct{}, len(cr.trailers))
	for k := range cr.trailers {
		wantTrailers[strings.ToLower(k)] = struct{}{}
	}
	input := bufio.NewScanner(bytes.NewReader(valueBuffer.Bytes()))
	for input.Scan() {
		line := strings.TrimSpace(input.Text())
		if line == "" {
			continue
		}
		// Find first separator.
		idx := strings.IndexByte(line, trailerKVSeparator[0])
		if idx <= 0 || idx >= len(line) {