public void TrackCount()
        {
            var seta = new ImmutableSet64().Add(1, 2, 4, 5, 6, 30, 31, 32, 33, 34);

            seta.Count.Should().Be(10);
            seta = seta.Intersect(new ImmutableSet64().Add(1, 2, 4, 8, 16, 32));
            seta.Count.Should().Be(4);
        }
        public void DetermineIntersectionWithEnumerable()
        {
            IImmutableSet <int> seta = new ImmutableSet64().Add(1, 2, 4, 8, 16, 32);
            var setb = Enumerable.Range(1, 5);

            seta.Intersect(setb)
            .SequenceEqual(new int[] { 1, 2, 4 })
            .Should()
            .BeTrue();
        }
        public void DetermineIntersectionWithSet()
        {
            var seta = new ImmutableSet64().Add(1, 2, 4, 8, 16, 32);
            var setb = new ImmutableSet64().Add(1, 2, 3, 4, 5);

            seta.Intersect(setb)
            .SequenceEqual(new int[] { 1, 2, 4 })
            .Should()
            .BeTrue();
        }