code: func (enc *Encoder) Encode(id uint64) string {
  
  	if id == 0 {
  		return string(enc.encode[:1])
  	}
  
  	bin := make([]byte, 0, binary.MaxVarintLen64)
  	for id > 0 {
  		bin = append(bin, enc.encode[id%58])
  		id /= 58
  	}
  
  	for i, j := 0, len(bin)-1; i < j; i, j = i+1, j-1 {
  		bin[i], bin[j] = bin[j], bin[i]
  	}
  
  	return string(bin)
  }
docs: // Encode returns encoded string by Base58.