amap_location/lib/bean/amap_marker.dart

class AmapMarker {
  double lat;
  double lon;
  Map<String, dynamic> extras;

  AmapMarker(this.lat, this.lon, this.extras);

  Map toMap() {
    Map map = {
      "lat": lat,
      "lon": lon
    };
    map.addAll(extras);
    return map;
  }
}