Adding Hive persistence

lib/services/hive_services.dart

@@ -0,0 +1,31 @@
+import 'package:hive_flutter/hive_flutter.dart';
+
+// constants
+const String kDataBox = "data";
+
+// sequence of ids
+const String kDataBoxIds = "ids";
+
+Future<void> openBoxes() async {
+  await Hive.initFlutter();
+  await Hive.openBox(kDataBox);
+}
+
+class HiveHandler {
+  late final Box dataBox;
+
+  HiveHandler() {
+    dataBox = Hive.box(kDataBox);
+  }
+
+  List<String>? getIds() => dataBox.get(kDataBoxIds) as List<String>?;
+  Future<void> setIds(List<String>? ids) => dataBox.put(kDataBoxIds, ids);
+
+  Map<String, dynamic>? getRequestModel(String id) =>
+      dataBox.get(id) as Map<String, dynamic>?;
+  Future<void> setRequestModel(
+          String id, Map<String, dynamic>? requestModelJson) =>
+      dataBox.put(id, requestModelJson);
+
+  Future<int> clear() => dataBox.clear();
+}