code: func (s *DefaultCookieProtector) NewToken(data []byte) ([]byte, error) {
  	nonce := make([]byte, cookieNonceSize)
  	if _, err := rand.Read(nonce); err != nil {
  		return nil, err
  	}
  	aead, aeadNonce, err := s.createAEAD(nonce)
  	if err != nil {
  		return nil, err
  	}
  	return append(nonce, aead.Seal(nil, aeadNonce, data, nil)...), nil
  }
docs: // NewToken encodes data into a new token.