type 'Future<dynamic>' is not a subtype of type 'Future<Map<dynamic, dynamic>>' in type cast

[agordeev]

I'm simply trying to instantiate the library:

flutterJs = FlutterJs();

but initEngine throws this error:

flutter: type 'Future<dynamic>' is not a subtype of type 'Future<Map<dynamic, dynamic>>' in type cast
flutter:
#0      FlutterJs.initEngine
flutter_js.dart:152
#1      new FlutterJs
flutter_js.dart:106

on this line:

    Map<dynamic, dynamic> mapResult = await (_methodChannel.invokeMethod(
        "initEngine", engineId) as Future<Map<dynamic, dynamic>>);