for _, v := range vectors {
		key, val, res, err := parsePAXRecord(v.in)
		ok := (err == nil)
		if ok != v.ok {
			if v.ok {
				t.Errorf("parsePAXRecord(%q): got parsing failure, want success", v.in)
			} else {
				t.Errorf("parsePAXRecord(%q): got parsing success, want failure", v.in)
			}
		}
		if v.ok && (key != v.wantKey || val != v.wantVal) {
			t.Errorf("parsePAXRecord(%q): got (%q: %q), want (%q: %q)",

	}
	return strings.TrimRight(fmt.Sprintf("%s%d.%09d", sign, secs, nsecs), "0")
}

// parsePAXRecord parses the input PAX record string into a key-value pair.
// If parsing is successful, it will slice off the currently read record and
// return the remainder as r.
func parsePAXRecord(s string) (k, v, r string, err error) {
	// The size field ends at the first space.
	nStr, rest, ok := strings.Cut(s, " ")

	// headers since 0.0 headers were not PAX compliant.
	var sparseMap []string

	paxHdrs := make(map[string]string)
	for len(sbuf) > 0 {
		key, value, residual, err := parsePAXRecord(sbuf)
		if err != nil {
			return nil, ErrHeader
		}
		sbuf = residual

		switch key {
		case paxGNUSparseOffset, paxGNUSparseNumBytes:
			// Validate sparse header order and value.