void onAdFailedToLoad(int errorCode)
 {
     if (errorCode == 302)
     {
         delegateObj.didFailtoShowInterstitial(errorCode + "");
     }
     else
     {
         delegateObj.didFailtoReceiveInterstitial("" + errorCode);
     }
 }
        private static void interstitialFailToShowCallback(IntPtr interstitialHandlePtr, string errorCode)
        {
            GCHandle interstitialHandle = (GCHandle)interstitialHandlePtr;
            AMRInterstitialViewDelegate delegateObject = interstitialHandle.Target as AMRInterstitialViewDelegate;

            if (errorCode.Equals("1081"))
            {
                delegateObject.didFailtoShowInterstitial(errorCode);
            }
            else
            {
                delegateObject.didFailtoReceiveInterstitial(errorCode);
            }
        }