Flutter how show markers in the circle? flutter_map

  android, dart, flutter, ios

newbie in Flutter. How show markers in the circle in flutter_map. Which day already trying to solve this problem. I can’t make the markers in the radius change, or just change color. That’s what i have achieved:

Position _currentPosition;
  static final List<LatLng> _points = [
    LatLng(55.749122, 37.659750),
    LatLng(55.770854, 37.626963),
    LatLng(55.776937, 37.637949),
    LatLng(55.739266, 37.637434),

  static const _markerSize = 40.0;
  List<Marker> _markers;
  List<CircleMarker> circle;

  void initState() {

    _markers = _points
          (LatLng point) => Marker(
        point: point,
        width: _markerSize,
        height: _markerSize,
        builder: (_) => Icon(Icons.location_on, size: _markerSize),


  _getCurrentLocation() {
        .getCurrentPosition(desiredAccuracy: LocationAccuracy.best)
        .then((Position position) {
      setState(() {
        _currentPosition = position;

    }).catchError((e) {

  Widget build(BuildContext context) {
    return FlutterMap(
      options: new MapOptions(
          minZoom: 16.0,
          center:  new LatLng(_currentPosition.latitude,_currentPosition.longitude)),
      layers: [new TileLayerOptions(urlTemplate: 'https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png',
          subdomains: ['a','b','c']),
        new MarkerLayerOptions(
            markers: [
              new Marker(
                  width: 45.0,
                  height: 45.0,
                  point: new LatLng(_currentPosition.latitude,_currentPosition.longitude),
                  builder: (context)=>new Container(
                    child: IconButton(icon: Icon(Icons.accessibility), onPressed: () {print('Marker tapped!');}),
      MarkerLayerOptions(markers: _markers),
      CircleLayerOptions(circles: [ CircleMarker(
          point: LatLng(_currentPosition.latitude,_currentPosition.longitude),
          color: Colors.blue.withOpacity(0.7),
          borderStrokeWidth: 2,
          useRadiusInMeter: true,
          radius: 2000 // 2000 meters | 2 km

my result – (this is image)

How to change the markers in the blue circle. For example change the marker icon?

Source: Android Questions