Dupe checker benchmark

var rand = new Random();

var stufff = Enumerable.Range(1, 1000).Select(i => rand.Next(1, 100000));


var sw = Stopwatch.StartNew();

for (int i = 0; i < 10000; i++)
{
    var nonNulls = stufff.Where(x => x != null);
    var dupes = nonNulls.Count() != nonNulls.Distinct().Count();
}

sw.Stop();

sw.ElapsedMilliseconds.Dump("Distinct");

var sw2 = Stopwatch.StartNew();

for (int i = 0; i < 10000; i++)
{

    var dupes = stufff
        .Where(item => item != null)
        .GroupBy(item => item)
        .Any(g => g.Count() > 1);
}

sw2.Stop();

sw2.ElapsedMilliseconds.Dump("Count");

var sw3 = Stopwatch.StartNew();

for (int i = 0; i < 10000; i++)
{

    var dupes = stufff
        .Where(item => item != null)
        .GroupBy(item => item)
        .Any(g => g.Skip(1).Any());
}

sw3.Stop();

sw3.ElapsedMilliseconds.Dump("Skip");