title: Mongo changestream timestamp
body: <p>When tailing the oplog, I see a timestamp for each event. Change streams have advantages over tailing the oplog directly, so I'd like to use those. However, I can't find any way of figuring out when a change occurred. This would be problematic if my script went down for a while and then resumed using a resume token.</p>
  
  <p>Is there any way of getting that timestamp?</p>