Xamarin async

Xamarin.Android

using System;
using System.Net.Http;
using System.Threading.Tasks;

using Android.App;
using Android.Content;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.OS;

namespace YouMeThemAndroid
{
  [Activity (Label = "YouMeThemAndroid", MainLauncher = true)]
	public class MainActivity : Activity
	{
		protected override void OnCreate (Bundle bundle)
		{
			base.OnCreate (bundle);
			SetContentView (Resource.Layout.Main);

			Button button = FindViewById<Button> (Resource.Id.myButton);

			button.Click += async delegate {
				var result = await Download();
				Console.WriteLine (result);
				button.Text = result;
			};
		}

		public async Task<string> Download()
		{
			HttpClient client = new HttpClient ();
			var result = await client.GetStringAsync("http://ip.jsontest.com");
			return result;
		}
	}
}

Xamarin.iOS

using System;
using System.Drawing;
using System.Net.Http;
using System.Threading.Tasks;

using MonoTouch.Foundation;
using MonoTouch.UIKit;

namespace YouMeThem
{
  public partial class YouMeThemViewController : UIViewController
	{
		public YouMeThemViewController () : base ("YouMeThemViewController", null)
		{
		}

		public override void ViewDidLoad ()
		{
			base.ViewDidLoad ();

			this.View.BackgroundColor = UIColor.Black;

			UIButton button = new UIButton (new RectangleF (10, 10, 100f, 100f)) {
				BackgroundColor = UIColor.Red
			};

			button.SetTitle ("Click Me", UIControlState.Normal);

			button.TouchUpInside += async delegate {
				var result = await Download();
				Console.WriteLine (result);
				button.SetTitle(result, UIControlState.Normal);
			};

			this.Add (button);
		}

		public async Task<string> Download()
		{
			HttpClient client = new HttpClient ();
			var result = await client.GetStringAsync("http://ip.jsontest.com");
			return result;
		}

	}
}