onInit method
Called immediately after the widget is allocated in memory. You might use this to initialize something for the controller.
Implementation
@override
void onInit() {
  dateStamp = DateTime.now().microsecondsSinceEpoch.toString();
  _eventListenerKey = "${dateStamp}_CometChatReactionListController";
  CometChatMessageEvents.addMessagesListener(_eventListenerKey, this);
  initializeReactionList();
  super.onInit();
}