Clojure-style atoms for C#

Atom.cs

using System;
using System.Threading;
using System.Threading.Tasks;

namespace Atom
{
    public class Atom<T> where T : class
    {
        private T _value;

        public Atom(T value)
        {
            _value = value;
        }

        public T Value => _value;

        public void Swap(Func<T, T> updater)
        {
            var sw = new SpinWait();

            while(true)
            {
                var curr = _value;
                var next = updater(curr);
                var result = Interlocked.CompareExchange(ref _value, next, curr);
                if (object.ReferenceEquals(result, curr))
                    break;

                sw.SpinOnce();
            }
        }
    }

    public class AtomTests
    {
        public static void Main(String[] args)
        {
            var atom = new Atom<string>("");

            Parallel.For(0, 100, _ => atom.Swap(x => "x" + x));

            Console.WriteLine($"{atom.Value} {atom.Value.Length}");
        }
    }
}