toJson method
Implementation
Map<String, dynamic> toJson() {
return {
'userId': userId,
'zipCode': zipCode,
'countryCode': countryCode,
'userAge': userAge,
'userGender': userGender?.toString().split('.').last,
'userSignupDate': userSignupDate?.millisecondsSinceEpoch,
'callbackParameters': callbackParameters,
};
}