static void 박싱2()
        {
            TestStruct t = new TestStruct(1, 1);
            Console.WriteLine(t);

            t.Change(2, 2);
            Console.WriteLine(t);

            Object o = t;
            Console.WriteLine(o);

            ((TestStruct)o).Change(3, 3);
            Console.WriteLine(t);
            Console.WriteLine(o);
            
        }

        struct TestStruct
        {
            private int a, b;
            public TestStruct(int a, int b)
            {
                this.a = a;
                this.b = b;
            }
            public void Change(int x, int y)
            {
                this.a = x;
                this.b = y;
            }

            public override string ToString()
            {
                return String.Format("{0},{1}", this.a.ToString(), this.b.ToString());
            }
        }

여기서 마지막 Console.WriteLine(o);가 3,3이아니고 2,2인 이유는 무엇인가요??