public void Naive_recursion_is_slow()
        {
            int fiboOf35 = FibonacciNaiveRecursion.IndexOf(35); //3.375 sec

            Check.That(fiboOf35).IsEqualTo(9227465);
        }
        public void Can_use_native_recursion(int index, int expected)
        {
            int actual = FibonacciNaiveRecursion.IndexOf(index);

            Check.That(actual).IsEqualTo(expected);
        }