updateCameraAngleForCurrentDeviceMotion calls UI API on a background thread

[jagatfx]

When running the example project on iOS 11.3 with Xcode 9.3, the Main Thread Checker detects that the UI API is called on a background thread instead of the main thread in updateCameraAngleForCurrentDeviceMotion() and Xcode reports -[UIApplication statusBarOrientation] must be used from main thread only on https://github.com/NYTimes/ios-360-videos/blob/develop/Sources/NYT360CameraController.m#L109.

After surrounding the code block by dispatch_async(dispatch_get_main_queue(), ^{ ... }); the warning no longer appears.

Main Thread Checker: UI API called on a background thread: -[UIApplication statusBarOrientation]
PID: 6294, TID: 2952262, Thread name: (none), Queue name: com.apple.scenekit.renderingQueue.SCNView0x10bd0c930, QoS: 33
Backtrace:
4   NYT360Video                         0x00000001047c9a48 -[NYT360CameraController updateCameraAngleForCurrentDeviceMotion] + 384
5   NYT360Video                         0x00000001047c8ea8 -[NYT360ViewController renderer:updateAtTime:] + 116
6   SceneKit                            0x0000000196c5af80 <redacted> + 444
7   SceneKit                            0x0000000196c5d018 <redacted> + 252
8   SceneKit                            0x0000000196c5d69c <redacted> + 84
9   SceneKit                            0x0000000196c5daa0 <redacted> + 728
10  SceneKit                            0x0000000196d0446c <redacted> + 512
11  SceneKit                            0x0000000196bc07dc <redacted> + 56
12  SceneKit                            0x0000000196ccd388 <redacted> + 80
13  libdispatch.dylib                   0x00000001047e9260 _dispatch_call_block_and_release + 24
14  libdispatch.dylib                   0x00000001047e9220 _dispatch_client_callout + 16
15  libdispatch.dylib                   0x00000001047f7e80 _dispatch_queue_serial_drain + 768
16  libdispatch.dylib                   0x00000001047ec730 _dispatch_queue_invoke + 328
17  libdispatch.dylib                   0x00000001047f8dd8 _dispatch_root_queue_drain_deferred_wlh + 352
18  libdispatch.dylib                   0x00000001047ffebc _dispatch_workloop_worker_thread + 676
19  libsystem_pthread.dylib             0x0000000182643e70 _pthread_wqthread + 860
20  libsystem_pthread.dylib             0x0000000182643b08 start_wqthread + 4
2018-04-24 16:27:12.053023+0800 NYT360VideoExample[6294:2952262] [reports] Main Thread Checker: UI API called on a background thread: -[UIApplication statusBarOrientation]
PID: 6294, TID: 2952262, Thread name: (none), Queue name: com.apple.scenekit.renderingQueue.SCNView0x10bd0c930, QoS: 33
Backtrace:
4   NYT360Video                         0x00000001047c9a48 -[NYT360CameraController updateCameraAngleForCurrentDeviceMotion] + 384
5   NYT360Video                         0x00000001047c8ea8 -[NYT360ViewController renderer:updateAtTime:] + 116
6   SceneKit                            0x0000000196c5af80 <redacted> + 444
7   SceneKit                            0x0000000196c5d018 <redacted> + 252
8   SceneKit                            0x0000000196c5d69c <redacted> + 84
9   SceneKit                            0x0000000196c5daa0 <redacted> + 728
10  SceneKit                            0x0000000196d0446c <redacted> + 512
11  SceneKit                            0x0000000196bc07dc <redacted> + 56
12  SceneKit                            0x0000000196ccd388 <redacted> + 80
13  libdispatch.dylib                   0x00000001047e9260 _dispatch_call_block_and_release + 24
14  libdispatch.dylib                   0x00000001047e9220 _dispatch_client_callout + 16
15  libdispatch.dylib                   0x00000001047f7e80 _dispatch_queue_serial_drain + 768
16  libdispatch.dylib                   0x00000001047ec730 _dispatch_queue_invoke + 328
17  libdispatch.dylib                   0x00000001047f8dd8 _dispatch_root_queue_drain_deferred_wlh + 352
18  libdispatch.dylib                   0x00000001047ffebc _dispatch_workloop_worker_thread + 676
19  libsystem_pthread.dylib             0x0000000182643e70 _pthread_wqthread + 860
20  libsystem_pthread.dylib             0x0000000182643b08 start_wqthread + 4