A generic Set type for .NET

using System;
using System.Collections;
using System.Collections.Generic;
using Lambda.Collections.Generic;
using System.Threading;
using System.Diagnostics;

public class Tests
{
    private const int N = 1000000;
    private static int[] values;
    static Tests()
    {
        //create a list of integers with lots of duplicate values;
        Random random = new Random();
        values = new int[N];
        for (int i = 0; i < N; i++)
            values[i] = random.Next(N / 10);
    }

    public delegate object TestDelegate();
    public static void Benchmark(TestDelegate testMethod)
    {
#if(DEBUG)
        Console.WriteLine("Warning: benchmarking in debug mode will not produce meaningful results!");
#endif
        ThreadPriority p = Thread.CurrentThread.Priority;
        try
        {
#if(!DEBUG)
            Thread.CurrentThread.Priority = ThreadPriority.Highest;
#endif
            DateTime time0, time1, endtime;
            //let the JIT do its thing for at least one second
            time0 = DateTime.Now;
            time1 = time0 + new TimeSpan(0, 0, 1);
            while ((endtime = DateTime.Now) < time1)
                testMethod();

            //benchmark for at least 10 seconds.
            long mem0 = System.GC.GetTotalMemory(true);
            time0 = DateTime.Now;
            time1 = time0 + new TimeSpan(0, 0, 10);
            int i = 0; object o = null;
            for (i = 0; (endtime = DateTime.Now) < time1; i++)
                o = testMethod();
            TimeSpan deltat = new TimeSpan((endtime.Ticks - time0.Ticks) / i);
            long mem1 = System.GC.GetTotalMemory(true);
            Console.WriteLine(
                "Method {0} took {1}",
                testMethod.Method.Name,
                deltat, o);
            Console.WriteLine(
                "The object returned consumes approx. {0} bytes after a full GC", mem1 - mem0);
        }
        finally
        {
            Thread.CurrentThread.Priority = p;
        }
    }
    public static object NonGenericHashSet()
    {
        Hashtable temp = new Hashtable();
        foreach (int i in values)
            temp[i] = null;
        return temp;
    }
    public static object GenericHashSet1()
    {
        Dictionary<int, object> temp = new Dictionary<int, object>();
        foreach (int i in values)
            temp[i] = null;
        return temp;
    }
    struct Dummy { };
    public static object GenericHashSet2()
    {
        Dummy dummy = new Dummy();
        Dictionary<int, int> temp = new Dictionary<int, int>();
        foreach (int i in values)
            temp[i] = 0;
        return temp;
    }
    public static object LambdaSet()
    {
        Set<int> s = new Set<int>();
        foreach (int i in values)
            s.Add(i);
        return s;
    }
    private static Set<int> Create(params int[] values)
    {
        return new Set<int>(values);
    }
    public static void Main(string[] args)
    {
        #region correctness tests
        Set<int> a = Create(1, 2, 3);
        Set<int> b = Create(3, 4, 5);
        Set<int> c = Create(1, 2, 3, 4);
        Trace.Assert((a & b) == Create(3));
        Trace.Assert((a | b) == Create(1, 2, 3, 4, 5));
        Trace.Assert((a ^ b) == Create(1, 2, 4, 5));
        Trace.Assert(a - b == Create(1, 2));
        Trace.Assert(b - a == Create(4, 5));
        Trace.Assert(a != c);
        Trace.Assert(a <= c);
        Trace.Assert(c >= a);
        Trace.Assert(a < c);
        Trace.Assert(c > a);
        #endregion
        #region speed tests
        Benchmark(NonGenericHashSet);
        Benchmark(GenericHashSet1);
        Benchmark(GenericHashSet2);
        Benchmark(LambdaSet);
        #endregion
        Console.ReadLine();
    }
}