title: Pagination for Firestore animated list flutter
body: <p>I'm making a chat app that messages should be shown on screen with nice animation and my backend is Firestore, so I decided to use this (<a href="https://pub.dev/packages/firestore_ui" rel="nofollow noreferrer">https://pub.dev/packages/firestore_ui</a>) plugin for animating messages.
  Now I want to implement pagination to prevent expensive works and bills. 
  Is there any way?
  How should I implement it?
  main problem is making a firestore animated list with <code>pagination</code>,
  It's easy to make simple <code>ListView</code> with pagination.
  as you can see in below code, this plugin uses <code>Query of snapShots</code> to show incoming messages (documents) with animation:</p>
  
  <pre><code>FirestoreAnimatedList(
      query: query,
      itemBuilder: (
          BuildContext context,
          DocumentSnapshot snapshot,
          Animation&lt;double&gt; animation,
          int index,
      ) =&gt; FadeTransition(
              opacity: animation,
              child: MessageListTile(
              index: index,
              document: snapshot,
              onTap: _removeMessage,
          ),
      ),
  );
  </code></pre>
  
  <p>if we want to use <code>AnimatedList</code> widget instead, we will have problem because we should track realtime messages(documents) that are adding to our collection.</p>