RestSharp formdata导致“流的意外结束”

Question

因此，我尝试使用以下文件上传文件：

private async Task Upload()
{
    string path = @"../../somepath";
    string url = "someurl/api/upload";
    var boundary = 12345;

    var client = new RestClient(url);

    RestRequest request = new RestRequest("/", Method.POST);
    request.AddHeader("Content-Type", "multipart/form-data; boundary=" + boundary);
    request.AddHeader("Accept", "application/json");

    request.AddFile("fileData", path);
    request.AlwaysMultipartFormData = true;

    request.AddParameter("key", "value", ParameterType.GetOrPost);

    var response = client.Execute(request);
}

但结果如下：

Unexpected end of Stream, the content may have already been read by another component。

有人暗示我在做什么错吗？