how to receive streaming response in Unity C#?

Question

I created a router using FastAPI python, which returns the StreamingResponse. But, I don't know how to receive and process the StreamingResponse in Unity C# scripts. the router is defined as follows.

@asr_router.post("/recognition_stream")
async def api_recognition_stream(to_simple: int = Body(1, description="是否繁体转简体", embed=True),
                                 remove_pun: int = Body(0, description="是否删除标点符号", embed=True),
                                 language: str = Body("zh", description="设置语言，简写，如果不指定则自动检测语言", embed=True),
                                 task: str = Body("transcribe", description="识别任务类型，支持transcribe和translate", embed=True),
                                 audio: UploadFile = File(..., description="音频文件")):
    global model_semaphore
    print("接收到数据！开始处理...")
    if language == "None": language = None
    if model_semaphore is None:
        model_semaphore = asyncio.Semaphore(5)
    await model_semaphore.acquire()
    contents = await audio.read()
    data = BytesIO(contents)
    generator = recognition(file=data, to_simple=to_simple, remove_pun=remove_pun, language=language, task=task)
    background_tasks = BackgroundTasks()
    background_tasks.add_task(release_model_semaphore)
    print("完成数据处理！开始进行数据推送...")
    return StreamingResponse(generator, background=background_tasks)

I've tried to receive the data chunk using UnityWebRequest.downloadHandler.data, but every time I can only get the first chunk.

        WWWForm form = new WWWForm();
        form.AddBinaryData("audio", audioBytes, "test.mp3", "audio/mpeg");
        UnityWebRequest www = UnityWebRequest.Post(m_SpeechRecognizeURL, form);
        Debug.Log("PostURL:" + m_SpeechRecognizeURL);
        www.SetRequestHeader("accept", "application/json");

        yield return www.SendWebRequest();
        if (www.result != UnityWebRequest.Result.Success)
        {
            Debug.LogError("Error sending audio file: " + www.error);
        }
        else
        {
            byte[] _responseByte = www.downloadHandler.data;
            string responseText = Encoding.Default.GetString(_responseBytes);
            // process json received then.
            Debug.Log(responseText);
            // _callback(_response.text);
        }

I am wondering how to get the other chunks in Stream response. Besides, to confirm correctness of the router, I've tested it in python using Request. It can return an iterator so I can iterate it to get data.