import 'package:json_annotation/json_annotation.dart'; part 'start_session_message.g.dart'; @JsonSerializable() class StartSessionMessage { @JsonKey(name: "desired_zip") late String desiredZip; StartSessionMessage(); factory StartSessionMessage.fromJson(Map json) => _$StartSessionMessageFromJson(json); Map toJson() => _$StartSessionMessageToJson(this); }