title: Firestore Snapshot Listener. How many can I listen before affect performance
body: <p>I'm developing a Chat style application that could potentially have tons of users chatting at the same time. I'm retrieving a list of chat-rooms when I enter on my Home screen and then adding an <code>SnapshotListener</code>to each one of the chat-rooms to listen the messages in real time. This can grow exponentially and I can end up having hundred or even thousands of <code>SnapshotListener</code> active at the same time on the client side.</p>
  
  <p>My question is, do this affect performance? I mean, regarding Firebase library, it has any kind of limit or performance issue when having that many listeners active at once? Of course not everyone is gonna be chatting at the same time, so even if there are 1000 open listeners, just 5-10 would be chatting and sending callbacks at once.</p>