import 'package:json_annotation/json_annotation.dart'; part 'header.g.dart'; @JsonSerializable() class Header { int? code; String? message; String? sid; int? status; Header({this.code, this.message, this.sid, this.status}); factory Header.fromJson(Map json) { return _$HeaderFromJson(json); } Map toJson() => _$HeaderToJson(this); }