I am seeing this crash (log at the bottom) after I am doing playing audio with AVAudioEngine. I know it might be related to the notification observer been released without calling removeObserver first. I have reviewed my code to make sure that removeObserver is called in the dealloc method. But to be sure, I have comment out adding all the observers that listens to any notification from the Audio engine but I am still getting this crash. It is much easier to reproduce if I use a bluetooth headphone. Any suggestions on how to debug this issue? I tried to printout the notification name with "po $arg1" ($arg2, or $arg3) but I get this error on the console
"(lldb) po $arg1
error: Couldn't materialize: couldn't read the value of register x0
Errored out in Execute, couldn't PrepareToExecuteJITExpression"
Thread 4Queue : engine (serial)
#0 0x000000019a4c1bd0 in objc_msgSend ()
#1 0x0000000185e123a4 in +[NSConcreteNotification newTempNotificationWithName:object:userInfo:] ()
#2 0x0000000185e122e0 in -[NSNotificationCenter postNotificationName:object:userInfo:] ()
#3 0x0000000101929d70 in _dispatch_call_block_and_release ()
#4 0x0000000101929d30 in _dispatch_client_callout ()
#5 0x0000000101935f64 in _dispatch_after_timer_callback ()
#6 0x0000000101929d30 in _dispatch_client_callout ()
#7 0x000000010194200c in _dispatch_source_latch_and_call ()
#8 0x000000010192c2d4 in _dispatch_source_invoke ()
#9 0x0000000101936a0c in _dispatch_queue_drain ()
#10 0x000000010192da20 in _dispatch_queue_invoke ()
#11 0x0000000101929d30 in _dispatch_client_callout ()
#12 0x0000000101938f38 in _dispatch_root_queue_drain ()
#13 0x0000000101938600 in _dispatch_worker_thread3 ()
#14 0x000000019aeb1478 in _pthread_wqthread ()