public async Task FetchTest()
        {
            Mac           mac    = new Mac(AccessKey, SecretKey);
            BucketManager target = new BucketManager(mac);

            HttpResult result = await target.FetchAsync(TestURL1, Bucket1, FileKey1);

            bool cond = (result.Code == (int)HttpCode.OK ||
                         result.Code == (int)HttpCode.BUCKET_NOT_EXIST ||
                         result.Code == (int)HttpCode.FILE_EXISTS);

            Assert.IsTrue(cond);
        }