title: How can I observe when user authenticates the app with biometrics?
body: <p>Simply in code I use it like this:</p>
  
  <pre><code>let context = LAContext()
  if context.canEvaluatePolicy(.deviceOwnerAuthentication, error: nil)
      context.evaluatePolicy(.deviceOwnerAuthentication, localizedReason: "jjj") { success, error in
          print(error)
          print(success)
      }
  }
  </code></pre>
  
  <p>Then user can see:</p>
  
  <p><a href="https://i.stack.imgur.com/twjiA.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/twjiA.png" alt="enter image description here"></a></p>
  
  <p>Everything is fine until user tap <code>Cancel</code>. Then I display label:</p>
  
  <p><code>"Please use biometrics to authenticate"</code>. NOW I need to get a callback after user was authenticated at any time after first try was cancelled. How can I detect this? </p>