The typical approach here as far as I'm aware is to use a deallocation queue - frees of an object that was allocated on another thread are freed by putting that

The typical approach here as far as I'm aware is to use a deallocation queue - frees of an object that was allocated on another thread are freed by putting that object in the original thread's deallocation queue. When that thread gets an opportunity, it frees everything in its deallocation queue to reclaim that memory.