Load data before Widget build in flutter

 @override
  initState() {
    super.initState();

    loadData().then((result) {
      print(result);
      setState(() {
       asyncWidget = result;
      });
    });
  }

  loadData() async {
    var widget = new AsyncWidget();
    return widget.build();
  }

  @override
  Widget build(BuildContext context) {

    if(asyncWidget == null) {
      return new Scaffold(
        appBar: new AppBar(
          title: new Text("Loading..."),
        ),
      );
    } else {
      return new Scaffold(
        appBar: new AppBar(
          title: new Text(widget.title),
        ),
        body: new Center(
          child: this.asyncWidget,
        ),
      );
    }
  }
}