Flutter Custom Icon Not Showing on Google Maps

Question

i am creating a custom BitmapDescriptor icon using a method, but when i pass the customMapMarker to the icon param the marker is not being shown on the screen. I think it has something to do with the setMarker method. It is being called in the initState() as the BitmapDescriptor returns a future to the customMarker

Code:

class MapScreen extends StatefulWidget {
  const MapScreen({Key? key}) : super(key: key);

  @override
  State<MapScreen> createState() => _MapScreenState();
}

class _MapScreenState extends State<MapScreen> {
  var markers = [];
  late BitmapDescriptor mapMarker;
  late GoogleMapController mapController;
  static final CameraPosition initicalCameraPosition = CameraPosition(
    target: LatLng(31.446893146741793, 74.27705705165864),
    zoom: 14.4746,
  );
  @override
  initState() {
    super.initState();
    setCustomMarker();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        leading: backButton(),
        backgroundColor: Colors.blue,
        elevation: 0,
        title: Center(
          child: Text(
            'Profile ',
            style: TextStyle(color: Colors.white),
          ),
        ),
      ),
      body: GoogleMap(
        initialCameraPosition: initicalCameraPosition,
        onMapCreated: onMapCreate,
        zoomControlsEnabled: false,
        // onTap: addMarker,
        markers: Set<Marker>.from(markers),
      ),
    );
  }

  void onMapCreate(GoogleMapController Controller) {
    mapController = Controller;
    animateCamera();
  }

  void animateCamera() {
    mapController
        .animateCamera(CameraUpdate.newCameraPosition(initicalCameraPosition));
  }

  addMarker() async {
    Marker marker = Marker(
        markerId: MarkerId('123'),
        infoWindow: InfoWindow(
            title: 'Muhammad Abdulreman', snippet: 'Blood Group: a+'),
        icon: mapMarker,
        position: LatLng(31.446893146741793, 74.27705705165864));
    setState(() {
      markers.add(marker);
    });
  }

  setCustomMarker() {
    mapMarker =
        BitmapDescriptor.defaultMarkerWithHue(BitmapDescriptor.hueAzure);
  }
}