Dart HttpRequest json授权错误：服务器响应401（未授权）

Question

我有servicestack并使用Restfull和Authenticate。

当我使用Dart对此代码进行身份验证时：

var request = new html.HttpRequest();
request.open('POST', "http://x.x.x.x:9998/auth/basic", async:false);
request.setRequestHeader("accept", "application/json");
request.setRequestHeader("content-type", "application/json");
request.setRequestHeader("authorization", "Basic YWRtaW46cGFzc3dvcmQ=");
request.send(null);
print(request.response); //OK -> Print {"SessionId":"1","UserName":"admin","ResponseStatus":{}}

...在我打电话给这项服务之前发生的事情：

request.open('GET', "http://x.x.x.x:9998/hello/everybody?format=json", async:false);
request.setRequestHeader("accept", "application/json");
request.setRequestHeader("content-type", "application/json");
request.setRequestHeader("authorization", "Basic YWRtaW46cGFzc3dvcmQ=");
request.send(null);
print(request.response);

...在request.send（null）;

给我错误输出显示

  

无法加载资源：服务器响应状态为401（未授权）   http://x.x.x.x:9998/hello/everybody?format=json

...给我打印好的输出显示（request.response）;

  

{“结果”：“你好，每个人”}

我的Dart代码有问题吗？这是正常的吗。