}
	return tw.writeRawHeader(blk, hdr.Size, hdr.Typeflag)
}

func (tw *Writer) writePAXHeader(hdr *Header, paxHdrs map[string]string) error {
	realName, realSize := hdr.Name, hdr.Size

	// TODO(dsnet): Re-enable this when adding sparse support.
	// See https://golang.org/issue/22735
	/*
		// Handle sparse files.
		var spd sparseDatas
		var spb []byte
		if len(hdr.SparseHoles) > 0 {

			Mode:       16877,
			Uid:        1000,
			Gid:        1000,
			Size:       14,
			ModTime:    time.Unix(1441973427, 0),
			Typeflag:   'D',
			Uname:      "rawr",
			Gname:      "dsnet",
			AccessTime: time.Unix(1441974501, 0),
			ChangeTime: time.Unix(1441973436, 0),
			Format:     FormatGNU,
		}, {
			Name:       "test2/foo",
			Mode:       33188,
			Uid:        1000,

		format.mayOnlyBe(FormatPAX)
	}
	for k, v := range paxHdrs {
		if !validPAXRecord(k, v) {
			return FormatUnknown, nil, headerError{fmt.Sprintf("invalid PAX record: %q", k+" = "+v)}
		}
	}

	// TODO(dsnet): Re-enable this when adding sparse support.
	// See https://golang.org/issue/22735
	/*
		// Check sparse files.
		if len(h.SparseHoles) > 0 || h.Typeflag == TypeGNUSparse {
			if isHeaderOnlyType(h.Typeflag) {

				Name:     "hi\x80\x81\x82\x83bye",
				Mode:     0644,
				Uid:      1000,
				Gid:      1000,
				Uname:    "rawr",
				Gname:    "dsnet",
				ModTime:  time.Unix(0, 0),
				Format:   FormatGNU,
			}, nil},
			testClose{nil},
		},
		// TODO(dsnet): Re-enable this test when adding sparse support.
		// See https://golang.org/issue/22735
		/*
			}, {
				file: "testdata/gnu-nil-sparse-data.tar",

// then writeTo uses Seek to skip past holes defined in Header.SparseHoles,
// assuming that skipped regions are filled with NULs.
// This always writes the last byte to ensure w is the right size.
//
// TODO(dsnet): Re-export this when adding sparse file support.
// See https://golang.org/issue/22735
func (tr *Reader) writeTo(w io.Writer) (int64, error) {
	if tr.err != nil {
		return 0, tr.err
	}
	n, err := tr.curr.WriteTo(w)