Reduced reproduction of data race inside Mono's System.Web.Caching.Cache

Program.cs

namespace ConsoleApplication10
{
    using System;
    using System.Linq;
    using System.Reflection;
    using System.Threading;
    using System.Web.Caching;

    internal class Program
    {
        public static void Main()
        {
            var cache = new Cache();
            
            var threads = new Action<Cache>[] { Adder, CheckGetKeyLastChange, CheckGetKeyLastChange, CheckGetKeyLastChange }
                .Select(x => new Thread(() => x(cache)) {IsBackground = true})
                .ToList();

            foreach (var t in threads)
            {
                t.Start();
            }

            foreach (var t in threads)
            {
                t.Join();
            }
        }

        private const int KeysCount = 30000; // 2x of HIGH_WATERMARK

        static void Adder(Cache cache)
        {
            try
            {
                while (true)
                {
                    for (var i = 0; i < KeysCount; ++i)
                    {
                        cache.Add(i.ToString(), i, null, DateTime.MaxValue, TimeSpan.Zero, CacheItemPriority.Default, null);
                    }
                    Console.Write("+");
                }
            }
            catch (Exception exception)
            {
                Console.WriteLine(exception);
                Environment.Exit(123);
            }
        }

        // Note: Cache.GetKeyLastChange is internal method; but it is called from several places and is a part of "public internal" cache API
        private static MethodInfo GetKeyLastChangeMethod = typeof(Cache).GetMethod("GetKeyLastChange", BindingFlags.Instance | BindingFlags.NonPublic);

        static void CheckGetKeyLastChange(Cache cache)
        {
            try
            {
                while (true)
                {
                    for (var i = 0; i < KeysCount; ++i)
                    {
                        GetKeyLastChangeMethod.Invoke(cache, new object[] {i.ToString()});
                    }
                    Console.Write("*");
                }
            }
            catch (Exception exception)
            {
                Console.WriteLine(exception);
                Environment.Exit(123);
            }
        }
    }
}