crash1

2017-07-25 22:09:39.428 Playgrounds.iOS[11144:809859] critical: Stacktrace:

2017-07-25 22:09:39.429 Playgrounds.iOS[11144:809859] critical:   at <unknown> <0xffffffff>
2017-07-25 22:09:39.430 Playgrounds.iOS[11144:809859] critical:   at (wrapper managed-to-native) CoreVideo.CVBuffer.CVBufferRelease (intptr) <0x00007>
2017-07-25 22:09:39.440 Playgrounds.iOS[11144:809913] -[__NSCFType trackingState]: unrecognized selector sent to instance 0x1c473dec0
2017-07-25 22:09:39.441 Playgrounds.iOS[11144:809859] critical:   at CoreVideo.CVBuffer.Dispose (bool) [0x00015] in /Users/builder/data/lanes/5024/218eee7c/source/xamarin-macios/src/CoreVideo/CVBuffer.cs:116
2017-07-25 22:09:39.441 Playgrounds.iOS[11144:809859] critical:   at CoreVideo.CVBuffer.Finalize () [0x00000] in /Users/builder/data/lanes/5024/218eee7c/source/xamarin-macios/src/CoreVideo/CVBuffer.cs:94
2017-07-25 22:09:39.442 Playgrounds.iOS[11144:809859] critical:   at (wrapper runtime-invoke) object.runtime_invoke_virtual_void__this__ (object,intptr,intptr,intptr) [0x0001e] in <675980d09e254fe988ac575901ca3701#F463C8C1-0A31-022A-8617-0B5511648B2C>:0
2017-07-25 22:09:39.442 Playgrounds.iOS[11144:809859] critical: 
Native stacktrace:

2017-07-25 22:09:39.443 Playgrounds.iOS[11144:809913] Xamarin.iOS: Received unhandled ObjectiveC exception: NSInvalidArgumentException -[__NSCFType trackingState]: unrecognized selector sent to instance 0x1c473dec0
Thread started:  #8
2017-07-25 22:09:39.478 Playgrounds.iOS[11144:809859] critical: 	0   libmonosgen-2.0.dylib               0x0000000102ee0800 mono_handle_native_crash + 224
2017-07-25 22:09:39.478 Playgrounds.iOS[11144:809859] critical: 	1   libmonosgen-2.0.dylib               0x0000000102eec7c8 mono_sigsegv_signal_handler + 316
2017-07-25 22:09:39.479 Playgrounds.iOS[11144:809859] critical: 	2   libsystem_platform.dylib            0x0000000184ce7b60 _sigtramp + 52
2017-07-25 22:09:39.479 Playgrounds.iOS[11144:809859] critical: 	3   libXamarin.iOS.dll.dylib            0x0000000102ad29c0 wrapper_managed_to_native_CoreVideo_CVBuffer_CVBufferRelease_intptr + 96
2017-07-25 22:09:39.479 Playgrounds.iOS[11144:809859] critical: 	4   libXamarin.iOS.dll.dylib            0x0000000102ad29c0 wrapper_managed_to_native_CoreVideo_CVBuffer_CVBufferRelease_intptr + 96
2017-07-25 22:09:39.479 Playgrounds.iOS[11144:809859] critical: 	5   libXamarin.iOS.dll.dylib            0x0000000102aae130 CoreVideo_CVBuffer_Dispose_bool + 64
2017-07-25 22:09:39.479 Playgrounds.iOS[11144:809859] critical: 	6   libXamarin.iOS.dll.dylib            0x0000000102aae064 CoreVideo_CVBuffer_Finalize + 36
2017-07-25 22:09:39.480 Playgrounds.iOS[11144:809859] critical: 	7   libmscorlib.dll.dylib               0x00000001015d7e54 wrapper_runtime_invoke_object_runtime_invoke_virtual_void__this___object_intptr_intptr_intptr + 100
2017-07-25 22:09:39.480 Playgrounds.iOS[11144:809859] critical: 	8   libmonosgen-2.0.dylib               0x0000000102f28508 mono_gc_run_finalize + 684
2017-07-25 22:09:39.480 Playgrounds.iOS[11144:809859] critical: 	9   libmonosgen-2.0.dylib               0x0000000102fbf6b8 sgen_gc_invoke_finalizers + 240
2017-07-25 22:09:39.480 Playgrounds.iOS[11144:809859] critical: 	10  libmonosgen-2.0.dylib               0x0000000102f29600 finalizer_thread + 772
2017-07-25 22:09:39.480 Playgrounds.iOS[11144:809859] critical: 	11  libmonosgen-2.0.dylib               0x0000000102f9a110 start_wrapper + 604
2017-07-25 22:09:39.480 Playgrounds.iOS[11144:809859] critical: 	12  libsystem_pthread.dylib             0x0000000184cec538 <redacted> + 256
2017-07-25 22:09:39.481 Playgrounds.iOS[11144:809859] critical: 	13  libsystem_pthread.dylib             0x0000000184cec438 <redacted> + 0
2017-07-25 22:09:39.481 Playgrounds.iOS[11144:809859] critical: 	14  libsystem_pthread.dylib             0x0000000184ceae48 thread_start + 4
2017-07-25 22:09:39.481 Playgrounds.iOS[11144:809859] critical: 
=================================================================
Got a SIGSEGV while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries 
used by your application.
=================================================================