代码如下：

 public IEnumerator SpeechRecognitionFunction(string wavStream)

    {

        WWWForm form = new WWWForm();

        Dictionary headers_m = form.headers;

        Debug.Log(headers_m["Content-Type"]);

        headers_m["Content-Type"] = "application/json";

        Debug.Log(headers_m["Content-Type"]);

        form.AddField("format", "wav");

        form.AddField("rate", 16000);

        form.AddField("channel", 1);

        form.AddField("cuid", cuid);

        form.AddField("token", "24.2ec95bb2717f4432cb8f8c8097903fb8.2592000.1480566308.282335-8811480");

        form.AddField("lan", "en");

        string filepath = Application.persistentDataPath + "/123.wav";

        FileStream fs = new FileStream(filepath, FileMode.Open);

        byte[] voice = new byte[fs.Length];

        fs.Read(voice, 0, voice.Length);

        fs.Close();

        fs.Dispose();

        string base64String = Convert.ToBase64String(voice);

        form.AddField("len", voice.Length);

        form.AddField("speech", base64String);

        byte[] rawData = form.data;

        Debug.Log(rawData.Length);

        //WWW www = new WWW(wavStream, form);

        WWW www_m = new WWW(wavStream, rawData, headers_m);

        yield return www_m;

        result_2 = www_m.text;

        result_m = www_m.text;

    }

之前看社区返回值是3300其中Sn为空的话说明Content-Type的问题，然而修改成"application/json"后依然返回3300，求助到底是怎么回事