title: How to route dead letter messages back to the original topic?
body: <p>I have a Google Cloud Pub/Sub subscription that is using a dead-letter topic. I recently had an outage that was preventing a number of messages from being processed &amp; they ended up in the dead-letter topic.</p>
  
  <p>The outage was resolved and I'd like to easily send the contents of dead letter subscription back to the original subscription. They're all present in the queue still (I have nothing consuming the dead letter sub) so I just need to route them somewhere.</p>
  
  <p>This is an admin task so I'd like it to be manually initiated, if that makes any difference. Ideally via the UI but I can't see anything there.</p>