dispose method
void
dispose()
Implementation
void dispose() {
debugPrint("delete frame_map_$mapIdMixin");
debugPrint("delete osm_map_$mapIdMixin");
html.window.document.getElementById("frame_map_$mapIdMixin")?.remove();
html.window.document.getElementById("osm_map_$mapIdMixin")?.remove();
//_div.remove();
_frame?.remove();
_frame = null;
//mapScript?.remove();
webPlatform.close(mapIdMixin);
channel = null;
webPlatform.mapsController.removeWhere((key, value) => key == mapIdMixin);
}