spb = append(strconv.AppendInt(spb, int64(len(spd)), 10), '\n')
			for _, s := range spd {
				hdr.Size += s.Length
				spb = append(strconv.AppendInt(spb, s.Offset, 10), '\n')
				spb = append(strconv.AppendInt(spb, s.Length, 10), '\n')
			}
			pad := blockPadding(int64(len(spb)))
			spb = append(spb, zeroBlock[:pad]...)
			hdr.Size += int64(len(spb)) // Accounts for encoded sparse map

		b.uint32(w.UncompressedSize)
	}
	_, err := w.zipw.Write(buf)
	return err
}

type countWriter struct {
	w     io.Writer
	count int64
}

func (w *countWriter) Write(p []byte) (int, error) {
	n, err := w.w.Write(p)
	w.count += int64(n)
	return n, err
}

type nopCloser struct {
	io.Writer
}

func (w nopCloser) Close() error {
	return nil
}