static <A> A waitForCalculatedValueUsingChangeListener(double timeout default infinity(), IF0<A> f, IHasChangeListeners sender) {
  new BoolVar trigger;
  
  temp tempOnChange(sender, -> trigger.set(true));
  
  while true {
    ping();
    try object f!;
    trigger.waitUntilTrueAndClear(timeout);
  }
}