如何使用DirectLIne上传文件？ C＃

Question

我尝试了above method！我收到错误的网关错误。

nuget包 Microsoft.Bot.Connector.DirectLine 3.0.2

uwp-目标版本17134，最低版本16299

代码

    var filePath = Path.Combine(ApplicationData.Current.LocalFolder.Path, speechFileName);
using (var stream = new FileStream(filePath, FileMode.Open, FileAccess.Read))
{
    using (var client = new HttpClient())
    {
        var uri = $@"https://directline.botframework.com/v3/directline/conversations/{_conversation.ConversationId}/upload?userId={_fromUser}";
        client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
        client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", DIRECT_LINE_SECRET);

        var content = new StreamContent(stream);
        content.Headers.ContentType = MediaTypeWithQualityHeaderValue.Parse("audio/wav");
        content.Headers.ContentDisposition = new ContentDispositionHeaderValue("file")
        {
            FileName = "text.wav"
        };
        var result = await client.PostAsync(uri, content);
        if (result != null)
        {
        }
    }
    stream.Flush();
}

响应

{StatusCode: 502, ReasonPhrase: 'Bad Gateway', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:
{
Server: Microsoft-IIS/10.0
Strict-Transport-Security: max-age=31536000
Cache-Control: no-cache
Date: Tue, 02 Oct 2018 07:27:58 GMT
Pragma: no-cache
Content-Length: 139
Content-Type: application/json; charset=utf-8
Expires: -1
}}
Content: {System.Net.Http.StreamContent}
Headers: {Server: Microsoft-IIS/10.0
Strict-Transport-Security: max-age=31536000
Cache-Control: no-cache
Date: Tue, 02 Oct 2018 07:27:58 GMT
Pragma: no-cache
}
IsSuccessStatusCode: false
ReasonPhrase: "Bad Gateway"
RequestMessage: {Method: POST, RequestUri: 'https://directline.botframework.com/v3/directline/conversations/EDX3Ectf9h93c11LozvGSG/upload?userId=kaki104', Version: 2.0, Content: System.Net.Http.StreamContent, Headers:
{
Authorization: Bearer iMU2qsXQSic.cwA.sjs.DUxL7a5bV-tnpYW79LpLMo8e22Klh8eT6nlGBfQc_FY
Content-Type: audio/wav
Content-Disposition: file; filename=text.wav
Content-Length: 10962
}}
StatusCode: BadGateway
Version: {1.1}

我需要在Bot中添加特殊设置吗？