* There's not a good accepted terminology for this kind of event, and for
historical reasons 'drawcall' has been the accepted term, even though
that can be quite confusing when a dispatch or a copy is a 'drawcall'.
* This is particularly highlighted by the event browser filters where
$draw() includes draws and dispatches, but $dispatch() only includes
dispatches, it's hard to intuitively understand why $draw() matches all
of these calls.
* As a result we've defined the term 'action' to cover these types of
events in the same way that we defined 'event' in the first place to
mean a single atomic API call.
* This is a very big blunt hammer for fixing the problem of multithreaded
submission from GL. Every GL call checks to see if the context changed (which
would only happen from a thread switch to a different context) and if detected
it inserts a manual MakeCurrent call equivalent.
* It's slow to capture (when this happens - checking is not particularly slow)
and slow to replay, but it's functional which is an improvement.
baldurk