code: func (e *Encoding) EncodeInt64(n int64) string {
  	var (
  		b   = make([]byte, 0)
  		rem int64
  	)
  
  	// Progressively divide by base, store remainder each time
  	// Prepend as an additional character is the higher power
  	for n > 0 {
  		rem = n % base
  		n = n / base
  		b = append([]byte{e.encode[rem]}, b...)
  	}
  
  	s := string(b)
  	if e.padding > 0 {
  		s = e.pad(s, e.padding)
  	}
  
  	return s
  }
docs: // EncodeInt64 returns the base62 encoding of n