WriteHeaders() call is missing in function Socket::writeJson()

void Socket::writeJson(const QJsonDocument &document, int statusCode)
{
   QByteArray data = document.toJson();
   setStatusCode(statusCode);
   setHeader("Content-Length", QByteArray::number(data.length()));
   setHeader("Content-Type", "application/json");
   **_writeHeaders();_**
   write(data);
   close();
}