title: Is there a way to define the starting tab in the navigation advanced sample?
body: <p>I am working on the project <a href="https://github.com/android/architecture-components-samples/tree/master/NavigationAdvancedSample" rel="nofollow noreferrer">NavigationAdvancedSample</a> of the 
  <a href="https://github.com/android/architecture-components-samples" rel="nofollow noreferrer">architecture-components-samples</a> repository. This project shows a workaround to support multiple back stacks for each tab of a <a href="https://developer.android.com/reference/com/google/android/material/bottomnavigation/BottomNavigationView?hl=en" rel="nofollow noreferrer">BottomNavigationView</a>.</p>
  
  <p>In this configuration, you define a navigation graph for each of your tabs and let the class extension <a href="https://github.com/android/architecture-components-samples/blob/master/NavigationAdvancedSample/app/src/main/java/com/example/android/navigationadvancedsample/NavigationExtensions.kt" rel="nofollow noreferrer">NavigationExtensions</a> handle the different back stacks for you. Everything works fine, but I can't find a way to select the starting tab of the <code>BottomNavigationView</code>. I have tried to tweak the <code>NavigationExtensions</code> but without success.</p>
  
  <p>By default, the selected tab on the application startup is the first of the bottom navigation view. How can I change this behavior in order to show the second or third tab for example?</p>