public void SimpleEnqueues()
        {
            var queue = ImmutableQueue <string> .Empty;

            Transactional.Enqueue(ref queue, "A");
            Transactional.Enqueue(ref queue, "B");

            queue.Should().BeEquivalentTo("A", "B");
        }
        public void SimpleEnqueuesWithFactory()
        {
            var queue = ImmutableQueue <int> .Empty;

            Transactional.Enqueue(ref queue, q => q.Count());             // 0
            Transactional.Enqueue(ref queue, q => q.Count());             // 1
            Transactional.Enqueue(ref queue, q => q.Count());             // 2
            Transactional.Enqueue(ref queue, q => q.Count());             // 3

            queue.Should().BeEquivalentTo(0, 1, 2, 3);
        }