code: func decode(token string) ([]byte, error) {
  	decoded, err := hex.DecodeString(token)
  	if err != nil {
  		return nil, trace.Wrap(err)
  	}
  
  	if len(decoded) != tokenLenBytes {
  		return nil, trace.BadParameter("invalid CSRF token byte length, expected %v, got %v", tokenLenBytes, len(decoded))
  	}
  
  	return decoded, nil
  }
docs: // decode decodes a cookie using base64.