This is a heads up to anyone using a manual KMDF queue. You MUST register
an EvtIoCanceledOnQueue routine, and that routine MUST complete the request
with STATUS_CANCELLED.
This is not at all clear from the docs (at least to me), which imply that
this routine is just notification that the request has already been canceled
by the framework.
I have given feedback on the doc section.
- Dan.