flutter navigation rebuild for stateless widgets

main.dart

import 'package:flutter/material.dart';

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Flutter Demo',
      theme: new ThemeData(
        primarySwatch: Colors.blue,
      ),
     home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatelessWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  void _goToNewScreen(BuildContext context) {
    Navigator.of(context).push(MaterialPageRoute(builder: (context) => Page2()));
  }

  @override
  Widget build(BuildContext context) {
    print("build");
    return new Scaffold(
      appBar: new AppBar(
        title: new Text(title),
      ),
      body: new Center(
        child: new Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            new Text(
              'Simple text',
              style: Theme.of(context).textTheme.display1,
            ),
          ],
        ),
      ),
      floatingActionButton: new FloatingActionButton(
        onPressed: () => _goToNewScreen(context),
        tooltip: 'GoTo2',
        child: new Icon(Icons.navigate_next),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

class Page2 extends StatelessWidget {

  @override
  Widget build(BuildContext context) {
    print("build page2");
    return Scaffold(
      appBar: AppBar(
        title: Text("page2"),
      ),
      body: Text("new page2"),
      floatingActionButton: FloatingActionButton(
        onPressed: () => _goToNewScreen2(context),
        tooltip: 'GoTo3',
        child: new Icon(Icons.navigate_next),
      ),
    );
  }

  void _goToNewScreen2(BuildContext context) {
    Navigator.of(context).push(MaterialPageRoute(builder: (context) {
      print("build page3");
      return Scaffold(
        appBar: AppBar(
          title: Text("page3"),
        ),
        body: Text("new page3"),
      );
      }
    )
    );
  }
}