Fix crash on exit when C# code was bound to asset unloading event called after C# shutdown

Source/Engine/Scripting/ManagedCLR/MCore.cpp

@@ -21,6 +21,7 @@
 MDomain* MRootDomain = nullptr;
 MDomain* MActiveDomain = nullptr;
 Array<MDomain*, FixedAllocation<4>> MDomains;
+bool MCore::Ready = false;
 
 MClass* MCore::TypeCache::Void = nullptr;
 MClass* MCore::TypeCache::Object = nullptr;
@@ -301,6 +302,11 @@ bool MProperty::IsStatic() const
     return false;
 }
 
+void MCore::OnManagedEventAfterShutdown(const char* eventName)
+{
+    LOG(Error, "Found a binding leak on '{}' event used by C# scripting after shutdown. Ensure to unregister scripting events from objects during disposing.", ::String(eventName));
+}
+
 MDomain* MCore::GetRootDomain()
 {
     return MRootDomain;

Source/Engine/Scripting/ManagedCLR/MCore.h

@@ -57,6 +57,10 @@ public:
     static void UnloadScriptingAssemblyLoadContext();
 #endif
 
+    // Utility for guarding against using C# scripting runtime after shutdown (eg. when asset delegate is not properly disposed).
+    static bool Ready;
+    static void OnManagedEventAfterShutdown(const char* eventName);
+
 public:
     /// <summary>
     /// Utilities for C# object management.

Source/Engine/Scripting/Runtime/DotNet.cpp

@@ -316,7 +316,8 @@ bool MCore::LoadEngine()
 
     char* buildInfo = CallStaticMethod<char*>(GetStaticMethodPointer(TEXT("GetRuntimeInformation")));
     LOG(Info, ".NET runtime version: {0}", ::String(buildInfo));
-    MCore::GC::FreeMemory(buildInfo);
+    GC::FreeMemory(buildInfo);
+    Ready = true;
 
     return false;
 }
@@ -327,6 +328,7 @@ void MCore::UnloadEngine()
         return;
     PROFILE_CPU();
     CallStaticMethod<void>(GetStaticMethodPointer(TEXT("Exit")));
+    Ready = false;
     MDomains.ClearDelete();
     MRootDomain = nullptr;
     ShutdownHostfxr();

Source/Tools/Flax.Build/Bindings/BindingsGenerator.Cpp.cs

@@ -2043,6 +2043,7 @@ namespace Flax.Build.Bindings
                     contents.Append(')').AppendLine();
                     contents.Append("    {").AppendLine();
                     contents.Append("        static MMethod* method = nullptr;").AppendLine();
+                    contents.AppendFormat("        if (!MCore::Ready) {{ MCore::OnManagedEventAfterShutdown(\"{0}.{1}\"); return; }}", classTypeNameManaged, eventInfo.Name).AppendLine();
                     contents.AppendFormat("        if (!method) {{ method = {1}::TypeInitializer.GetClass()->GetMethod(\"Internal_{0}_Invoke\", {2}); CHECK(method); }}", eventInfo.Name, classTypeNameNative, paramsCount).AppendLine();
                     contents.Append("        MObject* exception = nullptr;").AppendLine();
                     if (paramsCount == 0)