Processing order of late events is undefined

[olofson]

It seems like the "late API message" mechanism (which just clamps the timestamp to the start of the current frame) results in undefined processing order, and that's why we're having problems like olofson/koboredux#401 and olofson/koboredux#512.

[olofson]

I don't think this matters, actually - or rather, avoiding this issue does not solve the problem. After some experiments with this, I've concluded that the aforementioned Kobo Redux problems can occur even if messages arrive in order.

It seems like the problem is with creating or finding the A2_TNEWVOICE placeholder handles, which are to serve as event queues for voices not yet instantiated.

[olofson]

Turns out the Kobo Redux problems were eliminated by avoiding dropped messages due to API buffer overflows, so I'm leaving this for the next release.