title: List of visible items from QTreeView
body: <p>What's the best way to get the list of the currently visible items displayed by a QTreeView? And is it possible to get notifications when it changes?</p>
  
  <p>The data for my model can change asynchronously of the application (data comes from hardware registers). Refreshing that data can be slow, so I want to periodically refresh in a dedicated thread. I don't want to refresh all the items as it would be very inefficient, just the visible ones.</p>
  
  <p>I am aware of <a href="https://stackoverflow.com/questions/15817429/how-to-get-list-of-visible-qmodelindex-in-qabstractitemview">this</a>, but in my case the data changes asynchronously so I cannot refresh the items only when setData() is called.</p>