title: Delay message processing and delete before processing
body: <p>I need this ability to send push notifications for an action in a mobile app but wait for the user to undo the action until say 10 seconds.</p>
  
  <p>Is it possible to delay the processing of a message published in a topic by 10 seconds ? And then (sometimes, if user does undo) delete the message before 10 seconds, if it doesn't need to be processed ? </p>