Threaded model downloading not working for multiple models

Reported by user:

When I try to use the QThreadedDownloadManager (on Windows 7 using Qt built from git by setting the QT3D_MULTITHREAD env var) I do not get a network reply when downloading more than one mesh at the same time. As long as there is only one mesh to download it works fine, but I'm trying to download a sequence of meshes using threads in parallel

I'm expecting the finished() signal to trigger the doneWork() Slot that emits the downloadComplete() which eventually calls into: QAiSceneHandler::downloadComplete().This never happens and hence the mesh scenes are never loaded via the Urls.

In release mode I get the following QML output:

Download thread did not finish in timely manner - killing

Waiting for termination

The program has unexpectedly finished.

C:\Qt\Qt-Git\bin\qmlviewer.exe exited with code -805306369

When I use the QDownloadManager instead (by unsetting the QT3D_MULTITHREAD env var) all meshes load as expected. As the meshes (obj's) are not too big I can manage without the Threaded Download but ultimately this will be required as the mesh size and number of meshes in a sequence can be vary.