Method add

include/dmlc/concurrentqueue.h:1388–1399

    FreeList &operator=(FreeList const &) MOODYCAMEL_DELETE_FUNCTION;

    inline void add(N *node) {
#if 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() {
#if MCDBGQ_NOLOCKFREE_FREELIST