internal EventBasedParkSpot(EventBasedParkSpotFactory factory, IWaitBehavior waitBehavior) {
     this.factory = factory;
     this.waitBehavior = waitBehavior;
     psevent = new AutoResetEvent(false);
 }
 internal EventBasedParkSpot(EventBasedParkSpotFactory factory, IWaitBehavior waitBehavior)
 {
     this.factory      = factory;
     this.waitBehavior = waitBehavior;
     psevent           = new AutoResetEvent(false);
 }