Flutter RefreshIndicator, Async operation & setState - flutter

Question

I want to implement Refresh Indicator on my list view. On pulling the list down I'm calling an API to sync the list with server.
Now when I sync the list while I'm on the same page it refreshes the list.
But If I pop the screen by going back and again navigating to the same screen it doesn't refresh the list.
The sync is taking some time and the code for syncing is written in ChangeNotifier.
class ListScreen extends StatefulWidget {
const ListScreen({super.key});
#override
State<ListScreen> createState() => _ListScreenState();
}
class _ListScreenState extends State<ListScreen> {
int itemCount = 1;
SyncViewModel? _syncViewModel;
#override
Widget build(BuildContext context) {
_syncViewModel = context.watch<SyncViewModel>();
return Builder(builder: (context) {
return RefreshIndicator(
displacement: 250,
backgroundColor: Colors.yellow,
color: Colors.red,
strokeWidth: 3,
triggerMode: RefreshIndicatorTriggerMode.onEdge,
onRefresh: () async {
await _syncViewModel!.callSyncAPIs();
setState(() {
itemCount = itemCount + 1;
});
},
child: Scaffold(
backgroundColor: const Color(0xff246df8),
appBar: AppBar(
title: const Text('Refresh Indicator'),
backgroundColor: const Color(0xff246df8),
),
body: _buildCardDesign(),
),
);
});
}
import 'package:flutter/material.dart';
class SyncViewModel extends ChangeNotifier {
bool _loading = false;
bool get loading => _loading;
Future<void> callSyncAPIs() async {
_loading = true;
notifyListeners();
await Future.delayed(const Duration(seconds: 5));
_loading = false;
notifyListeners();
}
}
Earlier I was getting following exception, then I also checked for mounted before setState. But now in my use case the mounted is always false.
Exception has occurred.
FlutterError (setState() called after dispose(): _ListScreenState#5934b(lifecycle state: defunct, not mounted)
This error happens if you call setState() on a State object for a widget that no longer appears in the widget tree (e.g., whose parent widget no longer includes the widget in its build). This error can occur when code calls setState() from a timer or an animation callback.
The preferred solution is to cancel the timer or stop listening to the animation in the dispose() callback. Another solution is to check the "mounted" property of this object before calling setState() to ensure the object is still in the tree.
This error might indicate a memory leak if setState() is being called because another object is retaining a reference to this State object after it has been removed from the tree. To avoid memory leaks, consider breaking the reference to this object during dispose().)
How can I refresh the list when the sync completes If user navigates to the list page?
How can I show refreshing indicator if user navigates to the list page when sync is in progress?