docs: private boolean isOnSameActivity(String lastActivityInstanceId, String lastActivityId,
                                     String currentActivityInstanceId, String currentActivityId) {
      return
        //activityInstanceId's can be null on transitions, so the activityId must be equal
        ((lastActivityInstanceId == null && lastActivityInstanceId == currentActivityInstanceId && lastActivityId.equals(currentActivityId))
          //if activityInstanceId's are not null they must be equal -> otherwise execution changed
          || (lastActivityInstanceId != null && lastActivityInstanceId.equals(currentActivityInstanceId)
          && (lastActivityId == null || lastActivityId.equals(currentActivityId))));
  
    }