We call reportCall(with:, endedAt:, reason:) to end the call, mostly CXCallObserverDelegate func - (void)callObserver:(CXCallObserver *)callObserver callChanged:(CXCall *)call; will be called immediately with call end event.
But sometimes not like this, it will not callback, and after more then 20 seconds,
CXProviderDelegate func provider(_ provider: CXProvider, perform action: CXEndCallAction) will be call.
It seems not expected, and will cause callkit UI not disappear in a long time. So hy call end event not be call immediately by CXCallObserverDelegate func?