title: How to navigate to other page without animation Flutter
body: <p>I have a Login page, when I log on to go to the main page of my app i am using
  <code>Navigator.pushReplacement(context, new MaterialPageRoute(builder: (BuildContext context) =&gt; new Page1()));</code>
  But it have the slide animation, i want to disable it.</p>
  
  <p>this is my Material app format </p>
  
  <pre><code>class MyApp extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      return new MaterialApp(
        title: 'Flutter Demo',
        theme: new ThemeData(
          primarySwatch: Colors.blue,
        ),
        home: new Login(title: 'Login'),
        routes: &lt;String, WidgetBuilder&gt;{
          '/screen3': (BuildContext context) =&gt; new Page1(),
        },
      );
    }
  }
  </code></pre>