QNetworkRequest::CacheLoadControlAttribute PreferNetwork does not do network request

QNetworkAccessManager doesn't request a resource when a cache is set.

QNetworkAccessManager::setCache

I expect that when using QNetworkRequest::CacheLoadControlAttribute with PreferNetwork, I should be able to customize the cache behavior or have it handled automatically if the request header "If-Modified-Since" is set.

By "customize," I mean receiving a status code 304 when QNetworkReply::finished is emitted.

However, I only receive status 304 when I detach the cache from QNetworkAccessManager.

For an example demonstrating this issue, please see imagefetcher.cpp. I've added comments within the file.

NetworkCacheProblem.zip