Method add

concurrentqueue.h:1481–1493

		FreeList& operator=(FreeList const&) MOODYCAMEL_DELETE_FUNCTION;
		
		inline void add(N* node)
		{
#ifdef MCDBGQ_NOLOCKFREE_FREELIST
			debug::DebugLock lock(mutex);
#endif		
			// We know that the should-be-on-freelist bit is 0 at this point, so it's safe to
			// set it using a fetch_add
			if (node->freeListRefs.fetch_add(SHOULD_BE_ON_FREELIST, std::memory_order_acq_rel) == 0) {
				// Oh look! We were the last ones referencing this node, and we know
				// we want to add it to the free list, so let's do it!
		 		add_knowing_refcount_is_zero(node);
			}
		}
		
		inline N* try_get()
		{