title: CSV Download - Chrome issue
body: <p>On one of my routes, a CSV file is downloaded to the user with an incremental filename each time it is executed.</p>
  <p>I've hit some kind of caching issue in Chrome - subsequent executions download the original file - but Safari on a mac works fine every time.</p>
  <p>I've googled it, and added cache_timeout=0 - but that didn't resolve my issue. I don't want to generate a file in an IOstream as some others have suggested elsewhere. Any easy fixes, or shall I redirect to a URL with part of the filename embedded in the URL?</p>
  <pre><code>return send_file(path, as_attachment=True, cache_timeout=0)
  </code></pre>