Working exception dispatch

native/Avalonia.Native/inc/avalonia-native.h

@@ -308,6 +308,7 @@ AVNCOM(IAvnPlatformThreadingInterface, 0b) : IUnknown
     // Can't pass int* to sharpgentools for some reason
     virtual void Signal(int priority) = 0;
     virtual IUnknown* StartTimer(int priority, int ms, IAvnActionCallback* callback) = 0;
+    virtual HRESULT TerminateApp () = 0;
 };
 
 AVNCOM(IAvnSystemDialogEvents, 0c) : IUnknown

native/Avalonia.Native/src/OSX/platformthreading.mm

@@ -138,6 +138,12 @@ public:
             return new TimerWrapper(callback, ms);
         }
     }
+    
+    virtual HRESULT TerminateApp () override
+    {
+        [NSApp stop:0];
+        return S_OK;
+    }
 };
 
 @implementation Signaler

src/Avalonia.Native/CallbackBase.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Runtime.ExceptionServices;
 using SharpGen.Runtime;
+using Avalonia.Platform;
 
 namespace Avalonia.Native
 {
@@ -80,11 +81,12 @@ namespace Avalonia.Native
 
         public void RaiseException(Exception e)
         {
-            var threadingInterface = AvaloniaLocator.Current.GetService<PlatformThreadingInterface>();
-
-            threadingInterface.TerminateNativeApp();
+            if (AvaloniaLocator.Current.GetService<IPlatformThreadingInterface>() is PlatformThreadingInterface threadingInterface)
+            {
+                threadingInterface.TerminateNativeApp();
 
-            threadingInterface.DispatchException(ExceptionDispatchInfo.Capture(e));
+                threadingInterface.DispatchException(ExceptionDispatchInfo.Capture(e));
+            }
         }
     }
 }

src/Avalonia.Native/PlatformThreadingInterface.cs

@@ -99,7 +99,7 @@ namespace Avalonia.Native
 
         public void TerminateNativeApp()
         {
-            
+            _native.TerminateApp();
         }
 
         public void Signal(DispatcherPriority priority)