title: How to check progress of image upload to Firebase storage
body: <p>When the user registers for my app they choose a profile picture, input a name, email, and password. I use firebase to authenticate them using email and password. I am using <code>FIRAuth.auth()?.addAuthStateDidChangeListener</code>  to detect the change in a user's authentication status. If the user has been authenticated the code inside executes (this code sends the user to the next viewController). The problem is that the code inside fires off before my data can be added to the realtime database and FirebaseStorage. Is there a way to monitor when both tasks have succeeded so then I can trigger the change of view controllers? Thank you.</p>