CoreCLR has support for an NSAutoreleasePool for thread pool work items (dotnet/runtime#47592), but it's missing support for having an NSAutoreleasePool for every thread.

This issue is to track the required work in CoreCLR and in our own code.

Ref: dotnet/designs#197 (comment)
Ref: dotnet/designs#197 (comment)
Ref: dotnet/runtime#52023