public void Test_GetLastWriteTimeUtc()
        {
            var storage = new DiskIsolateStorage("Test", baseDirectory);

            storage.InitStore();
            string storePath = Path.Combine(baseDirectory, "Test");

            //创建目录
            string dir = "Test" + Guid.NewGuid().ToString();

            storage.CreateDirectory(dir);
            //在目录里创建文件
            string       testString = "This is teststring";
            MemoryStream stream     = new MemoryStream();

            byte[] buffer = Encoding.Default.GetBytes(testString);
            stream.Write(buffer, 0, 18);
            var filePath = dir + "/" + Guid.NewGuid().ToString() + ".txt";

            storage.CreateFile(filePath, stream);
            //修改文件内容
            FileStream fs = File.Open(Path.Combine(storePath, filePath), FileMode.Open);

            Byte[] info = new UTF8Encoding(true).GetBytes("This is some text in the file.");
            fs.Write(info, 0, info.Length);
            fs.Close();

            var dirLastWriteTime  = Directory.GetLastWriteTimeUtc(Path.Combine(storePath, dir));
            var fileLastWriteTime = File.GetLastWriteTimeUtc(Path.Combine(storePath, filePath));


            var dirResult  = storage.GetLastWriteTimeUtc(dir);
            var fileResult = storage.GetLastWriteTimeUtc(filePath);

            Assert.AreEqual(dirLastWriteTime, dirResult);
            Assert.AreEqual(fileLastWriteTime, fileResult);
        }