create static method
Implementation
static Future<IsolateMapfile> create(String filename, [String? preferredLanguage]) async {
IsolateMapfile _instance = IsolateMapfile._();
_instance._isolateInstance = await FlutterIsolateInstance.createInstance(
createInstance: _createInstanceStatic, instanceParams: _MapfileInstanceRequest(filename, preferredLanguage));
return _instance;
}