Android/Xamarin Bundle serialization

BundleSerializationExtensions.cs

using System;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;
using Android.OS;

namespace Serialization
{
	public static class BundleSerializationExtensions
	{
		public static void PutObject(this Bundle self, string key, object obj)
		{
			var formatter = new BinaryFormatter();
			var stream = new MemoryStream();

			formatter.Serialize(stream, obj);

			var bytes = stream.ToArray();

			self.PutByteArray(key, bytes);
		}

		public static T GetObject<T>(this Bundle self, string key)
			where T : class
		{
			if (self == null)
			{
				return default(T);
			}

			var bytes = self.GetByteArray(key);

			if (bytes == null) {
				return default(T);
			}

			var formatter = new BinaryFormatter();
			var stream = new MemoryStream(self.GetByteArray(key));

			return formatter.Deserialize(stream) as T;
		}
	}
}

MainActivity.cs

using Android.App;
using Android.Widget;
using Android.OS;

namespace Serialization
{
	[Activity(Label = "Serialization", MainLauncher = true, Icon = "@mipmap/icon")]
	public class MainActivity : Activity
	{
		State state;

		protected override void OnCreate(Bundle savedInstanceState)
		{
			base.OnCreate(savedInstanceState);

			state = savedInstanceState.GetObject<State>("state") ?? new State();

			// Set our view from the "main" layout resource
			SetContentView(Resource.Layout.Main);

			// Get our button from the layout resource,
			// and attach an event to it
			Button button = FindViewById<Button>(Resource.Id.myButton);

			button.Click += delegate { button.Text = $"{state.Count++} clicks!"; };
		}

		protected override void OnSaveInstanceState(Bundle outState)
		{
			base.OnSaveInstanceState(outState);

			outState.PutObject("state", state);
		}
	}
}

State.cs

using System;

namespace Serialization
{
	[Serializable]
	public class State
	{
		public int Count { get; set; }
	}
}