title: How to access the most recent scaffold in Flutter from the root ancestor?
body: <p>My app consists of a <code>StatefulWidget</code> at the root of the tree that passes its state along with callbacks to change the state to an <code>InheritedWidget</code>. Inside one of these callbacks a listener for a document inside Firebase's Firestore is created to listen for changes and then display a <code>SnackBar</code> informing the user about the change.</p>
  
  <p>The problem now is how to access the currently active <code>Scaffold</code> from the parent at the root of the tree. Between the root and the currently active <code>Scaffold</code> could be multiple other <code>Scaffolds</code> depending on how many routes were pushed onto the <code>Navigator</code>. But to display a <code>SnackBar</code> the most recent one must be used.</p>