public void TearDown()
        {
            var keys = new object[TransactionSynchronizationManager.ResourceDictionary.Keys.Count];

            TransactionSynchronizationManager.ResourceDictionary.Keys.CopyTo(keys, 0);
            foreach (var key in keys)
            {
                TransactionSynchronizationManager.UnbindResource(key);
            }

            TransactionSynchronizationManager.ClearSynchronization();

            _mongo.ClearReceivedCalls();
            _mongo = null;
            MongoTestHelper.ClearCache();
        }