feat(network-checker): single utils in client

Signed-off-by: Kapdroid <kapdroid@Kapdroids-MacBook-Pro.local>

Author: Kapdroid

lib/fa_flutter_api_client.dart

@@ -11,3 +11,4 @@ export 'src/api_options/api_options.dart';
 export 'src/interceptors/cache_interceptor.dart';
 export 'src/interceptors/cancel_token_interceptor.dart';
 export 'src/interceptors/refresh_token_interceptor.dart';
+export 'src/utils/network_checker.dart';

lib/src/utils/network_checker.dart

@@ -0,0 +1,24 @@
+import 'package:internet_connection_checker/internet_connection_checker.dart';
+
+class NetworkConnectivityService {
+  NetworkConnectivityService._internal()
+      : connectionChecker = InternetConnectionChecker.createInstance(
+          addresses: [
+            AddressCheckOption(uri: Uri.parse('https://www.google.com')),
+            AddressCheckOption(uri: Uri.parse('https://www.bing.com')),
+            AddressCheckOption(uri: Uri.parse('https://www.amazon.com')),
+            AddressCheckOption(uri: Uri.parse('https://www.cloudflare.com')),
+          ],
+        );
+
+  static NetworkConnectivityService? _instance;
+
+  static NetworkConnectivityService get instance {
+    _instance ??= NetworkConnectivityService._internal();
+    return _instance!;
+  }
+
+  final InternetConnectionChecker connectionChecker;
+
+  Future<bool> get isConnected => connectionChecker.hasConnection;
+}