if err != nil {
		return time.Time{}, ErrHeader
	}
	if len(sn) == 0 {
		return time.Unix(secs, 0), nil // No sub-second values
	}

	// Parse the nanoseconds.
	// Initialize an array with '0's to handle right padding automatically.
	nanoDigits := [maxNanoSecondDigits]byte{'0', '0', '0', '0', '0', '0', '0', '0', '0'}
	for i := range len(sn) {
		switch c := sn[i]; {
		case c < '0' || c > '9':