Crash in remove observer

[SamehDamuni]

__NSArrayM objectAtIndex:]: index 3 beyond bounds [0 .. 1]
1 CoreFoundation __exceptionPreprocess + 131
2 libobjc.A.dylib objc_exception_throw + 36
3 CoreFoundation -[__NSArrayM objectAtIndex:] + 216
4 CoreFoundation -[NSMutableArray removeObject:] + 120
5 Augury -[NSNotificationCenter(FXNotifications) FXNotification_removeObserver:name:object:] (FXNotifications.m:156)
6 Foundation -[NSNotificationCenter removeObserver:] + 26
7 Augury -[FXNotificationObserver dealloc] (FXNotifications.m:105)
8 libobjc.A.dylib objc_object::sidetable_release() + 236
9 Augury _destroy_helper_block (FXNotifications.m:0)
10 libsystem_blocks.dylib _Block_release + 128
11 Foundation -[NSBlockOperation dealloc] + 56
12 libobjc.A.dylib objc_object::sidetable_release() + 236
13 Foundation __NSOQSchedule_f + 430
14 libdispatch.dylib _dispatch_queue_serial_drain + 838
15 libdispatch.dylib _dispatch_queue_invoke + 564
16 libdispatch.dylib _dispatch_root_queue_drain + 376
17 libdispatch.dylib _dispatch_worker_thread3 + 104
18 libsystem_pthread.dylib 0x1B287937
19 libsystem_pthread.dylib

We had a crash while using your NSNotifications class.
we assume it's releated to more than one thread performing removeObserver causing inconsistency in the count of the array.
Any help will be appreciated!