Sample

void main() {
  runApp(App());
}
class App extends StatefulWidget {
  @override
  _AppState createState() => _AppState();
}

class _AppState extends State<App> {
  @override
  Widget build(BuildContext context) {
        return ChangeNotifierProvider<AgentsManager>(create: (_) => AgentsManager()),
          child: Consumer<AgentsManager>(builder: (context, agent, _) { 
            return ClientProvider(
                uri: Provider.of<AgentsManager>(context).loaded
                    ? Provider.of<AgentsManager>(context).httpLink
                    : "None",                      // The Agent Provider will have its httpLink attribute being able to change
                child: MaterialApp(               //But I need the app to rebuild in order for the changes to be seen elsewhere
                    debugShowCheckedModeBanner: false,
                    theme: manager.themeData,
                    initialRoute: '/',
                    routes: {
                      '/': (context) => LoginScreen(),
                      '/Homescreen': (context) => HomeScreen(),
                      '/Settings': (context) => SettingsScreen()
                    }));
          });
        }));
  }
}