onChatThreadEvent method
Implementation
@protected
void onChatThreadEvent(
    MultiDevicesEvent event, String chatThreadId, List<String> userIds) {
  for (var observer in List<ChatUIKitObserverBase>.of(observers)) {
    if (observer is MultiObserver) {
      observer.onChatThreadEvent(event, chatThreadId, userIds);
    }
  }
}