title: How to count the number of Snapshots that a Reference has?
body: <p>I'd like to know how can I count the number of snapshots that a Reference has inside of it in Firebase, so the next example I could get a value of 5.</p>
  
  <p> </p>
  
  <pre><code>    -TheReference
          -KoiWSAUZvT4RlBui4TY
          -KojK1uz0go1beOKPVtP
          -KooR3HzDcrGPq068t7T
          -KowcGAukSnUy5hjTUf5
          -KowtzW0SQYvbX87FAXN
  </code></pre>
  
  <p>I just want to count once the app starts and not in every database changes, so I'm not contemplating to use ValueEventListener or SingleValueEventListener over the reference.</p>
  
  <p>Is that possible? </p>