sbool waitForPredicateUsingChangeListener(IF0<Bool> pred, IHasChangeListeners sender) {
  new BoolVar trigger;
  
  temp tempOnChange(sender, -> {
    trigger.set(true);
  });
  
  while true {
    ping();
    if (pred!) true;
    trigger.waitUntilTrueAndClear();
  }
}