Method swap

concurrentqueue.h:1476–1476

		FreeList() : freeListHead(nullptr) { }
		FreeList(FreeList&& other) : freeListHead(other.freeListHead.load(std::memory_order_relaxed)) { other.freeListHead.store(nullptr, std::memory_order_relaxed); }
		void swap(FreeList& other) { details::swap_relaxed(freeListHead, other.freeListHead); }
		
		FreeList(FreeList const&) MOODYCAMEL_DELETE_FUNCTION;
		FreeList& operator=(FreeList const&) MOODYCAMEL_DELETE_FUNCTION;