code: func keyToString(k []byte) string {
  	if len(k) != lenHash {
  		panic(fmt.Sprintf("bad hash passed to hashToKey: %x", k))
  	}
  	return fmt.Sprintf("%s%x", hashPrefix, k)[0:lenKey]
  }
docs: // keyToString takes a key and returns a shortened and prefixed hexadecimal string version