public static void RemoveOnAdAvailabilityChangeMethod(AdColony.AdAvailabilityChangeDelegate onAdAvailabilityChange)
 {
     AdColony.OnAdAvailabilityChange -= onAdAvailabilityChange;
 }
 //-----------------
 public static void AddOnAdAvailabilityChangeMethod(AdColony.AdAvailabilityChangeDelegate onAdAvailabilityChange)
 {
     AdColony.OnAdAvailabilityChange += onAdAvailabilityChange;
 }