title: Android navigation component - change root fragment?
body: <p>let's say I have fragments a->b->c , but "a" is a splash screen, so I want "b" to become first fragment in stack and throw "a" forever, so when I'm i "b" and press "back" system button - I close the app</p>
  
  <p>In SupportFragmentManager I used replace() and that worked. But how can I achieve it here?</p>