title: Firebase uid returning nil after authentication (Swift)
body: <p>In my app, as soon as it opens I check to see if the user is already authenticated in the viewdidload of the initial view. If they are already authenticated, I perform a segue to the main view. I'm even printing the uid to the log at this time and it's printing correctly.</p>
  
  <pre><code>override func viewDidLoad() {
      super.viewDidLoad()
  
  
      if ref.authData != nil {
          let uid = ref.authData.uid
          print(uid)
  </code></pre>
  
  <p>I then do the same later in the app to get some of the user's info when they click on their profile settings. I write the exact same code to fetch their uid, but this time the uid is returning nil and is crashing with the error</p>
  
  <p>"fatal error: unexpectedly found nil while unwrapping an Optional value"</p>
  
  <p>Is this a firebase or simulator issue?</p>
  
  <p><em>Edit</em>: This issue has only occurred twice. Otherwise, the code itself works as intended, which makes me wonder whether it is a firebase or simulator issue.</p>