@protocol GADCustomEventInterstitialDelegate <NSObject>

Call back to this delegate in your custom event. You must call customEventInterstitialDidReceiveAd: when there is an ad to show, or customEventInterstitial:didFailAd: when there is no ad to show. Otherwise, if enough time passed (several seconds) after the SDK called the requestInterstitialAdWithParameter: method of your custom event, the mediation SDK will consider the request timed out, and move on to the next ad network.