title: Can google cloud pubsub subscription really be deleted automatically?
body: <p>From the doc:</p>
  
  <blockquote>
    <p>Subscriptions with no activity (push successes or pull requests) for 31 days may be deleted automatically</p>
  </blockquote>
  
  <p>I need to set up a push message subscription which usage may be very low (a few messages per year) but is vital to the app.</p>
  
  <p>The sentence above from the official documentation made me jump !
  Should I rely on google pubsub or move away from it ?
  Is there more information on this automatic mechanism ?</p>
  
  <p>Need advice.</p>