Closed/unresolvable library issue: Periodic/Intermittent crashes with AVFoundation

Problem occurs when starting a new player.  Not reliably reproducible.

Notes:
Outgoing song: 34 Payment for Treason.mp3
Incoming song: 08 Red Baron.mp3

Main player is in select() in football.

Pointers all compare in monitors and players.

Both audio players claim to be “Playing”.
However, outgoing player cue=false, incoming player cue=true.
	— Therefore cue() has been called but play() has not.

1.
Possibility: media item not retained, being lost?
Expect it to be retained/release by payer.

- Code change doesn’t fix it.

2.
Possibility: race condition in cue() when called from both daemon
thread and observer thread.  Modified cue() to avoid letting both
threads invoke AVPlayer:prerollAtRate::completionHandler concurrently.

Fail:
- Main thread has been observed in football’s select(), therefore it can’t be race condition.  Counter: Not true: the one thread might complete successfully and get to select() but leave a mishmash behind, causing the other to crash later.

3.
Possibility:  something related to release?
According to documentation, release *can* be queued until later.

However, on one incident of problem displayed while firing up player for the first time.
No release had occurred yet, no secondary player.

4. Run with zombies
No luck reproducing so far while running with zombies enabled.



Problem appears to be a buffer overflow in libdispatch.  Does not cause problems, but something out of range is being addressed.

Closed/not resolvable/no action.