func (r *Reader) UnreadRune() error {
	if r.i <= 0 {
		return errors.New("bytes.Reader.UnreadRune: at beginning of slice")
	}
	if r.prevRune < 0 {
		return errors.New("bytes.Reader.UnreadRune: previous operation was not ReadRune")
	}
	r.i = int64(r.prevRune)
	r.prevRune = -1
	return nil
}

// Seek implements the [io.Seeker] interface.

	offset int
}

func (d *openDir) Close() error               { return nil }
func (d *openDir) Stat() (fs.FileInfo, error) { return d.e.stat() }

func (d *openDir) Read([]byte) (int, error) {
	return 0, &fs.PathError{Op: "read", Path: d.e.name, Err: errors.New("is a directory")}
}

func (d *openDir) ReadDir(count int) ([]fs.DirEntry, error) {
	n := len(d.files) - d.offset
	if count > 0 && n > count {

}

// discard skips n bytes in r, reporting an error if unable to do so.
func discard(r io.Reader, n int64) error {
	// If possible, Seek to the last byte before the end of the data section.
	// Do this because Seek is often lazy about reporting errors; this will mask
	// the fact that the stream may be truncated. We can rely on the
	// io.CopyN done shortly afterwards to trigger any IO errors.