title: implementing firebase anonymous auth on ios flutter
body: <p>I'm looking at how to implement firebase anonymous auth on a flutter app. For android it works, but on the ios part it returns null.</p>
  <p>I'm guessing it has something to do with the <code>Appdelegate.swift</code>. If any can show me a code sample on how to implement this firebase anonymous auth in this swift file for flutter it would be a lot of help.</p>