public void ShouldChangeStructstate()
        {
            var p = new ChangeablePoint(1, 1);

            p.Change(2, 2);
            IChangable o = p;

            o.Change(3, 3);

            Assert.AreNotEqual(o, p);
        }
        public void ShouldBoxAndChange()
        {
            var p = new ChangeablePoint(1, 1);

            p.Change(2, 2);
            Object o = p;

            ((ChangeablePoint)o).Change(3, 3);
            var p2 = ((IChangable)p);

            p2.Change(4, 4);
            Assert.AreEqual(o, p);
            Assert.AreNotEqual(p2, o);
        }