WMSyncReader starts a background read thread that reads from the IStream passed to IWMSyncReader::OpenStream. This means it could use the IStream in the background even when no IWMSyncReader methods are being called.
For well-behaved applications, this is probably OK. However, AQUARIUM (Steam 2515070) frees the IStream it passes to WMSyncReader _before_ it calls IWMSyncReader::Close, which stops the read thread. This causes the read thread to access freed memory. This is improper, but not unreasonable, as IWMSyncReader is supposed to be a synchronous interface, so one might assume when they weren't calling into IWMSyncReader methods, the IStream won't be used.
This commit adds a `wg_parser_dont_read` function, which can be used to stop wg_parser from issuing read requests. This is used by IWMSyncReader to make sure read requests are only issued when IWMSyncReader methods are being called.
-- v5: DONT MERGE: winedebug in CI winegstreamer: Make sure WMSyncReader never reads in the background.