}
	}

	// Round ModTime and ignore AccessTime and ChangeTime unless
	// the format is explicitly chosen.
	// This ensures nominal usage of WriteHeader (without specifying the format)
	// does not always result in the PAX format being chosen, which
	// causes a 1KiB increase to every header.
	if tw.hdr.Format == FormatUnknown {
		tw.hdr.ModTime = tw.hdr.ModTime.Round(time.Second)
		tw.hdr.AccessTime = time.Time{}

		FileHeader: fh,
		offset:     uint64(w.cw.count),
	}

	if strings.HasSuffix(fh.Name, "/") {
		// Set the compression method to Store to ensure data length is truly zero,
		// which the writeHeader method always encodes for the size fields.
		// This is necessary as most compression formats have non-zero lengths
		// even when compressing an empty string.
		fh.Method = Store
		fh.Flags &^= 0x8 // we will not write a data descriptor