title: Firebase: Observe email verification status in real time
body: <p>How would I be able to check in real time if the user verified his email?</p>
  
  <p>My flow is like this:</p>
  
  <ol>
  <li>User registers</li>
  <li>Email is sent</li>
  <li>User sees "Please verify your email" notification</li>
  </ol>
  
  <p>Now I would like to:</p>
  
  <ol start="4">
  <li>setInterval -> check if email is verified</li>
  <li>If verified show the "Email verified" notification</li>
  </ol>
  
  <p>For this I would need a method that fetches the user data from firebase.
  Usually you just use the onAuthStateChanged callback to get userdata but I need to explicitly fetch current data.</p>
  
  <p>How would I do that?</p>