json dynamic casting

dynamic_casting_data.dart

class Container extends Coding {  
  List<String> things;

  @override
  Map<String, cast.Cast<dynamic>> get castMap => {
    "things": cast.List(cast.String)
  };
  

  @override
  void decode(KeyedArchive object) {
    super.decode(object);

    things = object.decode("things");
  }

  @override
  void encode(KeyedArchive object) {
    object.encode("things", things);
  }
}