code: func pkcs7encode(buf *bytes.Buffer, ignore, blockSize int) {
  	n := buf.Len() - ignore
  	more := blockSize - (n % blockSize)
  	for i := 0; i < more; i++ {
  		buf.WriteByte(byte(more))
  	}
  }
docs: // pkcs7encode is used to pad a byte buffer to a specific block size using
  // the PKCS7 algorithm. "Ignores" some bytes to compensate for IV