title: Sinch - callDidEstablish is not getting called on Lock screen while answering call from CallKit
body: <p>Sinch - <code>callDidEstablish</code> is not getting called on Lock screen while answering call from CallKit.</p>
  
  <p>I have integrated <code>CallKit</code> but answering call from Lock screen sinch call delegate method is not getting called to establish call.</p>
  
  <p>I also went through <code>iOS Sinch Document</code> it says :-</p>
  
  <blockquote>
    <p>Invoking -[SINCall answer] while being in the background is possible. The call is not immediately answered but the operation is considered pending and the call answered once the app returns to the foreground.</p>
  </blockquote>
  
  <p>Is there any way to establish call on answering it from Lock screen.</p>
  
  <p>Thanks in Advance.</p>