public void TryAddTest()
        {
            IWDT iwdt = new IWDT();

            Assert.IsTrue(iwdt.TryAdd(HT(1, 1), 4));

            Assert.AreEqual(4, iwdt.GetItem(HT(1, 2)));

            Assert.IsFalse(iwdt.TryAdd(HT(1, 3), 8));

            iwdt.Keys[Tuple.Create(1, 1)].IsGarbage = true;

            Assert.IsTrue(iwdt.TryAdd(HT(1, 3), 8));

            Assert.AreEqual(8, iwdt.GetItem(HT(1, 2)));
        }