init method
Implementation
void init(OsmWebWidgetState osmWebFlutterState, int idMap) {
debugPrint("idMap $idMap");
OSMPlatform.instance.init(mapIdMixin);
//mapIdMixin = idMap;
this.setWidgetState(osmWebFlutterState);
channel = MethodChannel('${FlutterOsmPluginWeb.getViewType(mapIdMixin)}');
debugPrint("in init _mapId $mapIdMixin");
}