QNetworkAccessManager does not discard network resources after emitation of QNetworkAccessManager::finished() signal if QNetworkReply::close() was called before request is finished.
A testbuild against Qt 4.8.6 works as expected.
I added a simple testcase with a Testserver called 'testserver.py' . The Testserver submits continuous 'garbage' data on an established connection until the client closes the connection.