title: CallKit in iOS 13: How to delay ringing?
body: <p>My VoIP app uses PJSIP. The incoming call scenario is:</p>
  
  <ol>
  <li>receive "Wakeup" push notification - this starts registering sip user and <strong>it takes some time</strong></li>
  <li>After registering SIP user, the asterisk is trying to route a call to the app - in this moment, the phone should start ringing</li>
  </ol>
  
  <p>In iOS 13 there is a required condition, that the CallKit has to be get notified about incoming call right in <code>didReceiveIncomingPushWithPayload</code> - which starts ringing. And I don't want this. I want to start ringing in the moment when the library receives SIP signal of an incoming call. But there is the SIP registering process between push notification and ringing. </p>
  
  <p>What is the best practice for this or what is the solution for that?</p>