Binding has not yet been initialized. when using isolates

Question

I got this error while I am using isolates

I am not able to use both compute function and Isolate.spawn function both gives the same error.

I have also written WidgetsFlutterBinding.ensureInitialized(); in the main function

but then also this error comes.

Future<void> main() async{
  WidgetsFlutterBinding.ensureInitialized();
  final AppController appController = Get.put(AppController());
  await appController.initializeSharedPreferencesAndDatabase();
  String? data =  appController.sharedPreferences!.getString(Constants.TOKEN);
  if(data != null){
    dataSaved = true;
  }
  else{
    dataSaved = false;
  }
  runApp(const MyApp());
}

This is my main function

await Isolate.spawn(Utilities.downloadPdf, [
                                pdfUrl,
                                name,
                                chapter,
                                subject,
                                documentId
                              ]);

here I am spawning my isolate like this.

This causes the error, I don't know why?

Please help