This searches for references to the S class that have unresolved getters. This gives you the option to create it with the id defined by the getter name. Example of main.dart file:

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      appBar: new AppBar(
        title: new Text(S.of(context).title),
      ),
      body: new Center(
        child: new Text(S.of(context).anotherString),
      ),
      floatingActionButton: new FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: S.of(context).increment,
        child: new Icon(Icons.add),
      ),
    );
  }