title: Add reward video to Xamarin android app IsLoaded always return false
body: <p>I'm trying to add a reward AdMob video to my app my code in onCreate is</p>
  
  <pre><code>Android.Gms.Ads.MobileAds.Initialize(ApplicationContext, "APP_CODE" );
  mRewardedVideoAd = MobileAds.GetRewardedVideoAdInstance(this);
  mRewardedVideoAd.RewardedVideoAdListener = this;
  mRewardedVideoAd.LoadAd(@"ca-app-pub-3940256099942544/5224354917",
                      new AdRequest.Builder().Build());
  </code></pre>
  
  <p>when i try to show the video by the following code</p>
  
  <pre><code>if (mRewardedVideoAd.IsLoaded)
                  mRewardedVideoAd.Show();
  </code></pre>
  
  <p>the mRewardedVideoAd.IsLoaded always return false</p>
  
  <p>Is There any solution for this?</p>