public bool ShowRewardedVideoAd(IAdsManagerCallback callback)
        {
            if (!Advertisement.IsReady(placementId) || currentCallback != null)
            {
                return(false);
            }

            currentCallback = callback;
            Advertisement.Show(placementId);

            return(true);
        }
        void IUnityAdsListener.OnUnityAdsDidFinish(string placementId, ShowResult showResult)
        {
            if (currentCallback != null)
            {
                if (showResult == ShowResult.Finished)
                {
                    currentCallback.AdWatched();
                }
                else
                {
                    currentCallback.AdSkipped();
                }
            }

            currentCallback = null;
        }