// io.CopyN done shortly afterwards to trigger any IO errors.
	var seekSkipped int64 // Number of bytes skipped via Seek
	if sr, ok := r.(io.Seeker); ok && n > 1 {
		// Not all io.Seeker can actually Seek. For example, os.Stdin implements
		// io.Seeker, but calling Seek always returns an error and performs
		// no action. Thus, we try an innocent seek to the current position
		// to see if Seek is really supported.

	return &ObjectReadSeekCloser{
		segmentReader: segmentReader,
		size:          actualSize,
		offset:        0,
		reader:        nil,
	}
}

// Seek call to implement io.Seeker
func (rsc *ObjectReadSeekCloser) Seek(offset int64, whence int) (int64, error) {
	// fmt.Printf("actual: %v offset: %v (%v) whence: %v\n", rsc.size, offset, rsc.offset, whence)
	switch whence {
	case io.SeekStart:

	}
}

func (sw *sparseFileWriter) ReadFrom(r io.Reader) (n int64, err error) {
	rs, ok := r.(io.ReadSeeker)
	if ok {
		if _, err := rs.Seek(0, io.SeekCurrent); err != nil {
			ok = false // Not all io.Seeker can really seek
		}
	}
	if !ok {
		return io.Copy(struct{ io.Writer }{sw}, r)
	}

	var readLastByte bool
	pos0 := sw.pos
	for sw.logicalRemaining() > 0 && !readLastByte && err == nil {

// TestReadTruncation test the ending condition on various truncated files and
// that truncated files are still detected even if the underlying io.Reader
// satisfies io.Seeker.
func TestReadTruncation(t *testing.T) {
	var ss []string
	for _, p := range []string{
		"testdata/gnu.tar",
		"testdata/ustar-file-reg.tar",
		"testdata/pax-path-hdr.tar",
		"testdata/sparse-formats.tar",

sekigahara.gifu.jp sekikawa.niigata.jp sel.no selbu.no select selfip.biz selfip.com selfip.info selfip.net selfip.org selje.no seljord.no sellfy.store sells-for-less.com sells-for-u.com sells-it.net sellsyourhome.org semboku.akita.jp semine.miyagi.jp senasa.ar sener sennan.osaka.jp senseering.net seoul.kr sera.hiroshima.jp seranishi.hiroshima.jp servebbs.com servebbs.net servebbs.org servebeer.com serveblog.net servecounterstrike.com serveexchange.com serveftp.com serveftp.net serveftp.org servegame.com servegame.org...