Native Admob Ads in Xamarin.Forms

I need to implement Native Ads in Xamarin.Forms. But I did not find any examples on Xamarin.Forms.
Maybe someone has an example of using Native Ads on Xamarin.Forms and can share.

My example of what I was trying to do:
Android:

[assembly: Dependency(typeof(NativeAd))]
namespace Ads.Droid.Platform.Renderers.Ad
{
    public class NativeAd : AdListener, INativeAd
    {
        Context context = Android.App.Application.Context;

       public void Show()
        {   
            var videoOptions = new VideoOptions.Builder().SetStartMuted(false).Build();
            var adOptions = new NativeAdOptions.Builder().SetVideoOptions(videoOptions).Build();
            AdLoader adLoader = new AdLoader.Builder(context, "ca-app-pub-3940256099942544/2247696110").WithNativeAdOptions(adOptions).Build();

            var request = new AdRequest.Builder();
            foreach (var item in TestDevice.GetTestDevices())
                request.AddTestDevice(item);

            adLoader.LoadAd(request.Build());   
        }
    }
}

or

[assembly: Dependency(typeof(NativeAd))]
namespace Ads.Droid.Platform.Renderers.Ad
{
    public class NativeAd : AdListener, INativeAd
    {
        NativeExpressAdView mAdView;

       public void Show()
        {   
            mAdView = new NativeExpressAdView(Android.App.Application.Context)
            {
                AdUnitId = "ca-app-pub-3940256099942544/2247696110",
                AdSize = AdSize.MediumRectangle
            };
            var request = new AdRequest.Builder();
            foreach (var item in TestDevice.GetTestDevices())
                request.AddTestDevice(item);
            mAdView.LoadAd(request.Build());    
        }
    }
}

In iOS didn’t do it, but I also need an example.
Maybe something needs to be changed or completed.
Help me please.