title: How to skip initial data and trigger only new updates in Firestore Firebase?
body: <p>I've searched everywhere with no luck. I want to query Firestore to get all users WHERE type is admin. Something like:</p>
  
  <pre><code>SELECT * FROM users WHERE type=admin
  </code></pre>
  
  <p>but <strong>only</strong> when the property <code>total</code> is changing. If I'm using:</p>
  
  <pre><code>users.whereEqualTo("type", "admin").addSnapshotListener(new EventListener&lt;QuerySnapshot&gt;() {
      @Override
      public void onEvent(@Nullable QuerySnapshot snapshots, @Nullable FirebaseFirestoreException e) {
          for (DocumentChange dc : snapshots.getDocumentChanges()) {
              switch (dc.getType()) {
                  case ADDED:
                      //Not trigger
                      break;
                  case MODIFIED:
                      //Trigger
                      break;
                  case REMOVED:
                      //
                      break;
              }
          }
      }
  });
  </code></pre>
  
  <p>The case ADDED is triggered first time when I query and when the <code>total</code> is changed <code>case MODIFIED</code> is triggered again (this is what is want). I want only changes and not the all initial data, I don't need it. How to get it?</p>
  
  <p>Please help me, is the last part of my project. How to skip is <code>case ADDED</code>?</p>