public void GetStreamFromBase64String()
        {
            {
                //不保存文件
                var ms = StreamUtility.GetStreamFromBase64String(baseString, null);

                Assert.AreEqual(21, ms.Length);

                //保存文件
                var file = UnitTestHelper.RootPath + "GetStreamFromBase64String.txt";
                var ms2  = StreamUtility.GetStreamFromBase64String(baseString, file);
                Assert.AreEqual(21, ms.Length);

                Assert.IsTrue(File.Exists(file));

                //读取文件
                using (var fs = new FileStream(file, FileMode.Open))
                {
                    using (var sr = new StreamReader(fs, Encoding.UTF8))
                    {
                        var content = sr.ReadToEnd();
                        Assert.AreEqual(str, content);
                    }
                }

                File.Delete(file);//删除文件
            }


            #region 测试异步方法
            Console.WriteLine("=== 测试异步方法 ===");
            Task.Run(async() =>
            {
                //不保存文件
                var ms = await StreamUtility.GetStreamFromBase64StringAsync(baseString, null);
                Assert.AreEqual(21, ms.Length);

                //保存文件
                var file = UnitTestHelper.RootPath + "GetStreamFromBase64String_Async.txt";
                var ms2  = await StreamUtility.GetStreamFromBase64StringAsync(baseString, file);
                Assert.AreEqual(21, ms.Length);

                Assert.IsTrue(File.Exists(file));

                //读取文件
                using (var fs = new FileStream(file, FileMode.Open))
                {
                    using (var sr = new StreamReader(fs, Encoding.UTF8))
                    {
                        var content = await sr.ReadToEndAsync();
                        Assert.AreEqual(str, content);
                    }
                }

                File.Delete(file);//删除文件

                Console.WriteLine("=== 异步完成 ===");
            }).GetAwaiter().GetResult();

            #endregion
        }