code: func (w *Writer) writeOffsetTable(entries []hashEntry) error {
  	w.buf2.Reset()
  	w.buf2.PutBE32int(len(entries))
  
  	for _, e := range entries {
  		w.buf2.PutUvarint(len(e.keys))
  		for _, k := range e.keys {
  			w.buf2.PutUvarintStr(k)
  		}
  		w.buf2.PutUvarint64(e.offset)
  	}
  
  	w.buf1.Reset()
  	w.buf1.PutBE32int(w.buf2.Len())
  	w.buf2.PutHash(w.crc32)
  
  	return w.write(w.buf1.Get(), w.buf2.Get())
  }
docs: // writeOffsetTable writes a sequence of readable hash entries.