import 'package:json_annotation/json_annotation.dart'; part 'acknowledge_message.g.dart'; @JsonSerializable() class AcknowledgeMessage { late String messageId; AcknowledgeMessage(); factory AcknowledgeMessage.fromJson(Map json) => _$AcknowledgeMessageFromJson(json); Map toJson() => _$AcknowledgeMessageToJson(this); }