Qt: How to stream data over a singlepart HTTP request in realtime?

Question

I have to stream data over a singlepart HTTP request in real time. The targeted device only handle data when request is like:

POST ...
Content-Type:...
Content-Length:9999999
Connection:Keep-Alive
Cache-Control:no-cache
Authorization:...

<data>
<data>
<data>
...

In Java, I have to do some hack to make it works using the setFixedLengthStreamingMode(9999999); function on my HttpURLConnection object. Then I create the request and populate body data with a BufferedOutputStream object.

Now, I'm trying to develop a Qt based application to transmit data to this device but I can't achieve it. I tried something like:

QNetworkRequest networkRequest;
networkRequest.setUrl(/*...*/);
// Set some headers
networkRequest.setHeader(QNetworkRequest::ContentLengthHeader, "9999999");

QIODevice* pIoDevice = new QBuffer(this);
pIoDevice->open(QIODevice::ReadWrite);

QNetworkAccessManager* pNetworkAccessManager = new QNetworkAccessManager(this);
pNetworkAccessManager->post(networkRequest, pIoDevice);

// Then exec current run loop to wait until I manually stop it.

On a other hand, when my producer give me data to transmit I's like to made something like:

pIoDeviceData->write(/* data */);

Problem is that reading network traces (using Wireshark), I see that the Content-Length emitted is equal to 0 so the device closes the connection and I get an error code NetworkError::RemoteHostClosedError; So I missed something but what? Any idea?