Simple example of a Widget build method without new keyword in Dart 2.

buildWidget.dart

Widget build(BuildContext context) => Scaffold(
  appBar: AppBar(
    title: Text(widget.title),
    actions: <Widget>[
      IconButton(
        icon: Icon(Icons.info),
        onPressed: _aboutAction,
      ),
      IconButton(
        icon: Icon(Icons.share),
        onPressed: _shareAction,
      )
    ],
  ),
  body: Center(
    child: _body(),
  ),
  floatingActionButton: FloatingActionButton(
    onPressed: _refresh,
    tooltip: 'Refresh',
    child: Icon(Icons.refresh),
  ),
);