C# BinaryFormatter works fine with readonly fields

ReadonlyFieldDeserialization.cs

using System;
using System.Diagnostics;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;

class Program
{
	static void Main()
	{
		var formatter = new BinaryFormatter();

		var stream = new MemoryStream();

		formatter.Serialize(stream, new Foo("test"));

		stream.Position = 0;

		var foo = (Foo)formatter.Deserialize(stream);

		Debug.Assert(foo.Bar == "test");
	}
}

[Serializable]
class Foo
{
	private readonly string _bar;

	public Foo(string bar)
	{
		_bar = bar;
	}

	public string Bar => _bar;
}