* yabridge runs the plugin's process function in a dedicated
bridged thread. Ardour's process thread is not (it just waits)
* When a plugin calls `restartComponent` from the realtime
thread. yabridge uses a host notification thread to perform
the callback.
Unlike other VST3 implementations that use a notification thread
(eg. JUCE), yabridge blocks and waits for the notification to
complete before the realtime thread can continue.
This leads to a deadlock.
However, we know that yabridge always synchronizes the
callback and concurrent calls are prevented by yabridge's design.
https://github.com/robbert-vdh/yabridge/issues/266
4402e2a3a8