Custom Marker in Flutter Getx or Normal in Statefull Widget

  Rx<BitmapDescriptor> markerIcon = BitmapDescriptor.defaultMarker.obs;  


void addCustomIcon() {
    BitmapDescriptor.fromAssetImage(
            const ImageConfiguration(), 'assets/svgs/logo.png')
        .then(
      (icon) {
        markerIcon.value = icon;
      },
    );
  }

Add marker in Marker List.

        markers.add(Marker(
            markerId: const MarkerId('Target location'),
            icon: markerIcon.value,
            // icon:
            //     //markerbitmap,
            //     BitmapDescriptor.defaultMarkerWithHue(BitmapDescriptor.hueRed),
            draggable: true,
            onDragEnd: (value) {
              print("marker Dragble Value ===> $value");
              // value is the new position
            },
            position: LatLng(lat!, long!),
            infoWindow: const InfoWindow(title: "My Target Location")));

and call it first onReady or OnInit Function

  @override
  void onReady() {
    addCustomIcon();

    // TODO: implement onReady
    super.onReady();
  }