Disabling a raster overlay causes crash in Debug build

[j9liu]

What happened?

Noticed while working on #612, but confirmed I could reproduce it on main.

Disabling a raster overlay (and especially one that is still loading) results in a crash Debug builds. I tried to look at the fields with the attached debugger, but it was hard to tell what was going on because a lot of variables were optimized out or garbage.

Received signal SIGSEGV
Obtained 52 stack frames
0x00007ffa39296574 (CesiumForUnityNative-Runtime) std::shared_ptr<CesiumRasterOverlays::IPrepareRasterOverlayRendererResources>::operator bool (at C:/Program Files/Microsoft Visual Studio/2022/Professional/VC/Tools/MSVC/14.38.33130/include/memory:1781)
0x00007ffa392960fc (CesiumForUnityNative-Runtime) CesiumRasterOverlays::RasterOverlayTile::~RasterOverlayTile (at C:/Dev/cesium-unity-samples/Packages/com.cesium.unity/native~/extern/cesium-native/CesiumRasterOverlays/src/RasterOverlayTile.cpp:46)
0x00007ffa38e114a8 (CesiumForUnityNative-Runtime) CesiumRasterOverlays::RasterOverlayTile::`scalar deleting destructor'
0x00007ffa38e13d34 (CesiumForUnityNative-Runtime) CesiumUtility::ReferenceCounted<CesiumRasterOverlays::RasterOverlayTile,0>::releaseReference (at C:/Dev/cesium-unity-samples/Packages/com.cesium.unity/native~/extern/cesium-native/CesiumUtility/include/CesiumUtility/ReferenceCounted.h:89)
0x00007ffa38ec71e4 (CesiumForUnityNative-Runtime) CesiumUtility::IntrusivePointer<CesiumRasterOverlays::RasterOverlayTile>::operator= (at C:/Dev/cesium-unity-samples/Packages/com.cesium.unity/native~/extern/cesium-native/CesiumUtility/include/CesiumUtility/IntrusivePointer.h:174)
0x00007ffa392995fd (CesiumForUnityNative-Runtime) CesiumRasterOverlays::TileProviderAndTile::~TileProviderAndTile (at C:/Dev/cesium-unity-samples/Packages/com.cesium.unity/native~/extern/cesium-native/CesiumRasterOverlays/src/ActivatedRasterOverlay.cpp:356)
0x00007ffa392a27c8 (CesiumForUnityNative-Runtime) CesiumRasterOverlays::TileProviderAndTile::`scalar deleting destructor'
0x00007ffa392a2082 (CesiumForUnityNative-Runtime) async::detail::task_result_holder<CesiumRasterOverlays::TileProviderAndTile>::~task_result_holder<CesiumRasterOverlays::TileProviderAndTile> (at C:/Users/Janine.Liu/.ezvcpkg/dbe35ceb30c688bf72e952ab23778e009a578f18/installed/x64-windows-unity/include/async++/task_base.h:202)
0x00007ffa392a201c (CesiumForUnityNative-Runtime) async::detail::task_result<CesiumRasterOverlays::TileProviderAndTile>::~task_result<CesiumRasterOverlays::TileProviderAndTile> (at C:/Users/Janine.Liu/.ezvcpkg/dbe35ceb30c688bf72e952ab23778e009a578f18/installed/x64-windows-unity/include/async++/task_base.h:271)
0x00007ffa3929c693 (CesiumForUnityNative-Runtime) async::detail::task_func<async::detail::inline_scheduler_impl,async::detail::continuation_exec_func<async::detail::inline_scheduler_impl,async::task<CesiumRasterOverlays::TileProviderAndTile>,CesiumRasterOverlays::TileProviderAndTile,CesiumAsync::CesiumImpl::CatchFunction<`CesiumRasterOverlays::ActivatedRasterOverlay::doLoad'::`2'::<lambda_3>,CesiumRasterOverlays::TileProviderAndTile,CesiumAsync::CesiumImpl::ImmediateScheduler<CesiumAsync::CesiumImpl::QueuedScheduler>,async::task<CesiumRasterOverlays::TileProviderAndTile> &&>,std::integral_constant<bool,0>,1>,CesiumRasterOverlays::TileProviderAndTile>::~task_func<async::detail::inline_scheduler_impl,async::detail::continuation_exec_func<async::detail::inline_scheduler_impl,async::task<CesiumRasterOverlays::TileProviderAndTile>,CesiumRasterOverlays::TileProviderAndTile,CesiumAsync::CesiumImpl::CatchFunction<`CesiumRasterOverlays::ActivatedRasterOverlay::doLoad'::`2'::<lambda_3>,CesiumRasterOverlays::TileProviderAndTile,CesiumAsync::CesiumImpl::ImmediateScheduler<CesiumAsync::CesiumImpl::QueuedScheduler>,async::task<CesiumRasterOverlays::TileProviderAndTile> &&>,std::integral_constant<bool,0>,1>,CesiumRasterOverlays::TileProviderAndTile> (at C:/Users/Janine.Liu/.ezvcpkg/dbe35ceb30c688bf72e952ab23778e009a578f18/installed/x64-windows-unity/include/async++/task_base.h:427)
0x00007ffa3929c708 (CesiumForUnityNative-Runtime) async::detail::task_func<async::detail::inline_scheduler_impl,async::detail::continuation_exec_func<async::detail::inline_scheduler_impl,async::task<CesiumRasterOverlays::TileProviderAndTile>,CesiumRasterOverlays::TileProviderAndTile,CesiumAsync::CesiumImpl::CatchFunction<`CesiumRasterOverlays::ActivatedRasterOverlay::doLoad'::`2'::<lambda_3>,CesiumRasterOverlays::TileProviderAndTile,CesiumAsync::CesiumImpl::ImmediateScheduler<CesiumAsync::CesiumImpl::QueuedScheduler>,async::task<CesiumRasterOverlays::TileProviderAndTile> &&>,std::integral_constant<bool,0>,1>,CesiumRasterOverlays::TileProviderAndTile>::`scalar deleting destructor'
0x00007ffa3929c6cb (CesiumForUnityNative-Runtime) async::detail::task_func<async::detail::inline_scheduler_impl,async::detail::continuation_exec_func<async::detail::inline_scheduler_impl,async::task<CesiumRasterOverlays::TileProviderAndTile>,CesiumRasterOverlays::TileProviderAndTile,CesiumAsync::CesiumImpl::CatchFunction<`CesiumRasterOverlays::ActivatedRasterOverlay::doLoad'::`2'::<lambda_3>,CesiumRasterOverlays::TileProviderAndTile,CesiumAsync::CesiumImpl::ImmediateScheduler<CesiumAsync::CesiumImpl::QueuedScheduler>,async::task<CesiumRasterOverlays::TileProviderAndTile> &&>,std::integral_constant<bool,0>,1>,CesiumRasterOverlays::TileProviderAndTile>::destroy (at C:/Users/Janine.Liu/.ezvcpkg/dbe35ceb30c688bf72e952ab23778e009a578f18/installed/x64-windows-unity/include/async++/task_base.h:432)

Environment

Cesium for Unity version: v1.18.1
Unity Editor Version: 2022.3.55.f1
Operating System: Windows

Reproduction steps

1. Open 01_CesiumWorld in Cesium for Unity Samples,
2. Disable the raster overlay on Cesium World Terrain.
3. Observe the crash.

Supporting evidence

Editor.log