import 'package:json_annotation/json_annotation.dart'; part 'track_message.g.dart'; @JsonSerializable() class TrackMessage { TrackPosition? pos; TrackMessage(); factory TrackMessage.fromJson(Map json) => _$TrackMessageFromJson(json); Map toJson() => _$TrackMessageToJson(this); } @JsonSerializable() class TrackPosition { late String time; late double lat; late double long; late int acc; TrackPosition(); factory TrackPosition.fromJson(Map json) => _$TrackPositionFromJson(json); Map toJson() => _$TrackPositionToJson(this); }