func (c *MapClaims) MarshalJSON() ([]byte, error) {
	json := jsoniter.ConfigCompatibleWithStandardLibrary
	return json.Marshal(c.MapClaims)
}

// ParseWithStandardClaims - parse the token string, valid methods.
func ParseWithStandardClaims(tokenStr string, claims *StandardClaims, key []byte) error {
	// Key is not provided.
	if key == nil {
		// keyFunc was not provided, return error.