TF-1317 Show push notification on background or terminated app

model/lib/model.dart

@@ -74,4 +74,6 @@ export 'upload/file_info.dart';
 export 'upload/upload_response.dart';
 // User
 export 'user/user_profile.dart';
-export 'user/user_profile_response.dart';
+export 'user/user_profile_response.dart';
+// Notification
+export 'notification/notification_payload.dart';

model/lib/notification/notification_payload.dart

@@ -0,0 +1,31 @@
+
+import 'dart:convert';
+
+import 'package:equatable/equatable.dart';
+import 'package:jmap_dart_client/http/converter/email_id_nullable_converter.dart';
+import 'package:jmap_dart_client/http/converter/state_nullable_converter.dart';
+import 'package:jmap_dart_client/jmap/core/state.dart' as jmap;
+import 'package:jmap_dart_client/jmap/mail/email/email.dart';
+import 'package:json_annotation/json_annotation.dart';
+
+part 'notification_payload.g.dart';
+
+@EmailIdNullableConverter()
+@StateNullableConverter()
+@JsonSerializable(explicitToJson: true, includeIfNull: false)
+class NotificationPayload with EquatableMixin {
+
+  final EmailId? emailId;
+  final jmap.State? newState;
+
+  NotificationPayload({this.emailId, this.newState});
+
+  factory NotificationPayload.fromJson(Map<String, dynamic> json) => _$NotificationPayloadFromJson(json);
+
+  Map<String, dynamic> toJson() => _$NotificationPayloadToJson(this);
+
+  String get encodeToString => jsonEncode(toJson());
+
+  @override
+  List<Object?> get props => [emailId, newState];
+}