Add markers to the map.
MapManager.addMarker()
final marker = await _mapManager.addMarker( MapManagerMarkerOptions( coordinate: MapManagerLatLng( latitude: 37.7749, longitude: -122.4194, ), isSelectable: true, ), ); print("Marker's annotationID is ${marker.annotationID}.");
_mapManager.removeAnnotations(MapManagerRemoveAnnotationsArguments());
_mapManager?.removeAnnotations( MapManagerRemoveAnnotationsArguments(tag: '123456'), );
_mapManager.removeAnnotation( MapManagerRemoveAnnotationArguments(annotationID: 'markerId'), );