title: What's the correct way to implement login page in Xamarin Shell?
body: <p>My app has structure like this.</p>
  
  <p>Splash page => Login page => Main page</p>
  
  <p>After login, user cannot go back to login/splash page. There are several pages in flyout menu that user can go to. However, login/splash items should not be showed in these flyout menu items.</p>
  
  <p>Some project may try to load main page first before show login page as a modal page. I think this way doesn't work because it should take so much time to load complex main page before send user back to login.</p>