public void Test1() {

            byte[] bytes = new byte[] { 0xFF, 0xFF, 0xFF, 0xFF, 0x00 };
            BigInteger reverseme = new BigInteger(bytes);
            BigInteger reversed = reverseme.PositiveReverse(4);

            Assert.AreEqual(0, (int)reversed);


        }
        public void Test2() {

            byte[] bytes = new byte[] { 0xFF, 0xFF, 0xFF, 0xFF, 0x00 };
            BigInteger reverseme = new BigInteger(bytes);
            BigInteger reversed = reverseme.PositiveReverse(8);
            var result = reversed.ToByteArray();

            Assert.AreEqual(0x0, result[0]);
            Assert.AreEqual(0x0, result[1]);
            Assert.AreEqual(0x0, result[2]);
            Assert.AreEqual(0x0, result[3]);
            Assert.AreEqual(0xFF, result[4]);
            Assert.AreEqual(0xFF, result[5]);
            Assert.AreEqual(0xFF, result[6]);
            Assert.AreEqual(0xFF, result[7]);


        }