Get real upload progress in QT - c++

Question

So I want to upload a file using this code in qt:
QFile *file = new QFile(this->itemsToUpload.at(index));
QUrl url("http://leonardogalli.ch/beta/upload_single.php");
QNetworkRequest request(url);
QHttpMultiPart *multiPart = new QHttpMultiPart(QHttpMultiPart::FormDataType);
QHttpPart loginPart;
/* password */
loginPart.setHeader(QNetworkRequest::ContentDispositionHeader, QVariant("form-data; name=\"password\""));
loginPart.setBody("pass");
multiPart->append(loginPart);
loginPart.setHeader(QNetworkRequest::ContentDispositionHeader, QVariant("form-data; name=\"path\""));
loginPart.setBody(this->paths.at(index).toLocal8Bit());
qDebug() << this->paths.at(index).toLocal8Bit();
multiPart->append(loginPart);
QHttpPart filePart;
/* important that the files[] variable have the brackets, for PHP to interpret correctly */
filePart.setHeader(QNetworkRequest::ContentDispositionHeader, QVariant("form-data; name=\"uploaded\"; filename=\""+ file->fileName() + "\""));
qDebug() << "form-data; name=\"file1\"; filename=\""+ file->fileName() + "\"";
file->open(QIODevice::ReadOnly);
//qDebug() << file->readAll();
filePart.setBodyDevice(file);
file->setParent(multiPart); // we cannot delete the file now, so delete it with the multiPart
multiPart->append(filePart);
QNetworkReply* reply = networkManager->post(request, multiPart);
this->currentReply = reply;
multiPart->setParent(reply); // delete the multiPart with the reply
QObject::connect(reply,SIGNAL(uploadProgress(qint64,qint64)), this, SLOT(uploadProgress(qint64,qint64)));
QObject::connect(reply, SIGNAL(finished()), this, SLOT(finished()));
QObject::connect(reply, SIGNAL(downloadProgress(qint64,qint64)), this, SLOT(downloadProgress(qint64,qint64)));
}
void UploadManager::uploadProgress(qint64 bytesSent, qint64 bytesTotal)
{
if(bytesSent!=0 && bytesTotal != 0)
{
qDebug() << "Uploaded:" << bytesSent << " bytes of total: " << bytesTotal << "diff to total: " << bytesTotal-this->totalSize;
qint64 bytesDiff = bytesSent - this->lastUlSize;
this->UlSize += bytesDiff;
this->lastUlSize = bytesSent;
int timeDiff = QDateTime::currentMSecsSinceEpoch()/1000-this->time;
if(timeDiff!= 0 && bytesSent!=0 && bytesTotal != 0)
{
qDebug() << "Uploadspeed: " << ((this->UlSize/timeDiff));
qint64 remainingUl = this->totalSize - this->UlSize;
qint64 speed = ((this->UlSize/timeDiff)); //Download Speed in B/s
int remainingTimeSec = remainingUl/speed;
qDebug() << "Remaining time: " << this->readableTime(remainingTimeSec) << " percentage: " << (this->UlSize/this->totalSize)*100;
float percentage = ((float)this->UlSize/(float)this->totalSize)*100;
emit uploadProg(this->niceSpeed(speed), this->readableTime(remainingTimeSec), percentage);
}
}
}
The problem is there is a really long delay between the last uploadProgress signal and the finished signal. According to this question this is due to the uploadProgress not being the progress when a chunk of data has finished uploading. So how would I get the real uploadProgress, when a chunk is finished uploading?
Update 1:
On mac it seems to work perfectly, so why wont it work on windows?