title: Django - show loading message during long processing
body: <p>How can I show a <em>please wait</em> loading message from a django view?</p>
  
  <p>I have a Django view that takes significant time to perform calculations on a large dataset.  </p>
  
  <p>While the process loads, I would like to present the user with a feedback message e.g.: spinning loading animated gif or similar.</p>