With recent changes in QgsNetworkAccessManager this should be
safe to resurrect (fingers crossed!). Also simplify code a lot,
because now QgsNetworkAccessManager handles waking the worker
thread after the auth request is handled.
Add a lot more tests
This new class, QgsBlockingNetworkRequest, is designed for
performing SAFE blocking requests. It is thread safe and
has full support for QGIS proxy and authentication settings.
This class should be used whenever a blocking network
request is required. Unlike implementations
which rely on QApplication::processEvents() or creation of a
QEventLoop, this class is completely
thread safe and can be used on either the main thread or
background threads without issue.
Redirects are automatically handled by the class.
After completion of a request, the reply content should be
retrieved by calling getReplyContent().
This method returns a QgsNetworkReplyContent container,
which is safe and cheap to copy and pass
between threads without issue.
The guts of this class have been copied from QgsWfsRequest (which
has been using the same approach since 3.2)
