title: How do you pop to a specific screen in react-navigation StackNavigator?
body: <p>I am trying to find <code>StackNavigator</code>'s to <code>UINavigationContoller</code>'s <code>popToViewController(_ viewController: UIViewController, animated: Bool)</code>.</p>
  
  <p>According to the docs <code>goBack()</code> only ever goes back one position, the argument you pass in is where you are going back <em>from</em> rather than where you want to go back <em>to</em>.</p>
  
  <p>There are no tabs or nesting of navigators just a simple A->B->C->D->E with the ability to go back to <em>any</em> of the previous screens from E.</p>