Dictionary comparison

public static void Benchmark()
    {
        var iterations = 1000;
        var size       = 100000;
        for (var i = 0; i < size; i++)
        {
            concurrent.Add(i.ToString(), i);
            simple.Add(i.ToString(), i);
            threadSafe.Add(i.ToString(), i);
        }

        var sw  = Stopwatch.StartNew();
        var max = 0;
        for (var it = 0; it < iterations; it++)
        {
            Parallel.For(0, size, i =>
            {
                concurrent.TryGetValue(i.ToString(), out var element);
                if (element > max)
                    max = element;
            });
        }

        sw.Stop();
        Console.WriteLine($"concurrent: {sw.Elapsed}");

        sw = Stopwatch.StartNew();
        max = 0;
        for (var it = 0; it < iterations; it++)
        {
            Parallel.For(0, size, i =>
            {
                threadSafe.TryGetValue(i.ToString(), out var element);
                if (element > max)
                    max = element;
            });
        }

        sw.Stop();
        Console.WriteLine($"thread-safe: {sw.Elapsed}");

        sw = Stopwatch.StartNew();
        var rw = new ReaderWriterLockSlim();
        max = 0;
        for (var it = 0; it < iterations; it++)
        {
            Parallel.For(0, size, i =>
            {
                rw.EnterReadLock();
                try
                {
                    simple.TryGetValue(i.ToString(), out var element);
                    if (element > max)
                        max = element;
                }
                finally
                {
                    rw.ExitReadLock();
                }
            });
        }

        sw.Stop();
        Console.WriteLine($"rw + simple: {sw.Elapsed}");

        sw = Stopwatch.StartNew();
        max = 0;
        for (var it = 0; it < iterations; it++)
        {
            Parallel.For(0, size, i =>
            {
                lock (simple)
                {
                    simple.TryGetValue(i.ToString(), out var element);
                    if (element > max)
                        max = element;
                }
            });
        }

        sw.Stop();
        Console.WriteLine($"lock + simple: {sw.Elapsed}");

        sw = Stopwatch.StartNew();
        max = 0;
        for (var it = 0; it < iterations; it++)
        {
            Parallel.For(0, size, i =>
            {
                simple.TryGetValue(i.ToString(), out var element);
                if (element > max)
                    max = element;
            });
        }

        sw.Stop();
        Console.WriteLine($"no lock: {sw.Elapsed}");
    }