private static extern void FBInterstitialAdBridgeOnWillClose(int uniqueId,
                                                              FBInterstitialAdBridgeExternalCallback callback);
 private static extern void FBInterstitialAdBridgeOnWillClose(int uniqueId,
                                                              FBInterstitialAdBridgeExternalCallback callback);
 private static extern void FBInterstitialAdBridgeOnImpression(int uniqueId,
                                                               FBInterstitialAdBridgeExternalCallback callback);
 private static extern void FBInterstitialAdBridgeOnImpression(int uniqueId,
                                                               FBInterstitialAdBridgeExternalCallback callback);