急于实现onPress触发器时执行Future，async和await吗？

调用onPressed时如何实现Future，async和await。我有一个Container1，那里有一个凸起的按钮，可导航到Container2。 Container2有一个图像。我要等待图像加载，并且在图像加载完成后应完成其他操作。按下reaised按钮时如何执行此操作。

货柜1

class Container1 extends StatefulWidget {
  @override
  _Container1State createState() => _Container1State();
}

class _Container1State extends State<Container1> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: RaisedButton(
          child: Text('Next Page'),
          onPressed: () {
            Navigator.push(
              context,
              MaterialPageRoute(
                builder: (context) => Container2(),
              ),
            );
          },
        ),
      ),
    );
  }
}

货柜2

class Container2 extends StatefulWidget {
  @override
  _Container2State createState() => _Container2State();
}

class _Container2State extends State<Container2> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Container(
              height: 250,
              width: 150,
              child: Image.asset('images/pic.jpg'),
            ),
            RaisedButton(
              child: Text('Back'),
              onPressed: () {
                Navigator.pop(context);
              },
            ),
          ],
        ),
      ),
    );
  }
}