Method MarkTaken

include/vk_mem_alloc.h:8925–8925

        void MarkFree() { prevFree = VMA_NULL; }
        void MarkTaken() { prevFree = this; }
        bool IsFree() const { return prevFree != this; }
        void*& UserData() { VMA_HEAVY_ASSERT(!IsFree()); return userData; }
        Block*& PrevFree() { return prevFree; }