我有一个可以使用hive的类，我想接收我正在使用的api的列表，但是当我调用得到列表的类时，它会给我这个错误

class PersistStorage {
  sendData(List<Movie> movie) async {
    var box = await Hive.openBox('data');
    box.put("movies", movie);
  }

}

futurebuilder，我称之为我的班级：

class GridViewMovies extends StatefulWidget {
  double _crossAxisSpacing = 15, _mainAxisSpacing = 12, _aspectRatio = 1;
  PersistStorage storage;

  GridViewMovies({Key key}) : super(key: key);

  @override
  _GridViewMoviesState createState() => _GridViewMoviesState();
}

class _GridViewMoviesState extends State<GridViewMovies> {
  BlocMovies movieBloc;

  @override
  Widget build(BuildContext context) {
    movieBloc = BlocProvider.of(context);

    return FutureBuilder(
        future: movieBloc.getlistMovies(),
        builder: (BuildContext context, AsyncSnapshot<MoviesModel> snapshot) {
          switch (snapshot.connectionState) {
            case ConnectionState.waiting:
              return Center(
                child: CircularProgressIndicator(),
              );
              break;
            case ConnectionState.none:
              return Center(
                child: CircularProgressIndicator(),
              );
              break;

            case ConnectionState.done:
              if (snapshot.data == null) {
                return Center(child: Text("Intenta mas tarde"));
              }
              //here call my function .......................
              widget.storage.sendData(snapshot.data.items);

              return Center(
                child: movieList(context, snapshot.data.items),
              );
              break;

            case ConnectionState.active:
              if (snapshot.data == null) {
                return Center(child: Text("Intenta mas tarde"));
              }
              return Center(
                child: movieList(context, snapshot.data.items),
              );

              break;
            default:
          }
        });
  }

因为这个类只服务于调用我的函数，但却给了我那个错误，所以有什么办法解决这个问题吗？