title: Add (not replace) fragment with navigation architecture component
body: <p>I have an activity with a product list fragment and many other fragments and I am trying to use architecture component navigation controller.</p>
  <p>The problem is: it replaces the (start destination) product list fragment and I don't want the list to be reloaded when user click back button.</p>
  <p>How to make the fragment transaction as add not replace?</p>