move ref count into msg meta, only 1 poinetr now.

lichao

2021-04-23 dc86ace85e437ecb8a2e728e4dce36d02bbb8a6e

 utest/speed_test.cpp

@@ -39,12 +39,12 @@
      body.set_topic("topic");
      body.set_data(str);
      auto head(InitMsgHead(GetType(body), proc_id));
      msg.MakeRC(shm, head, body);
      assert(msg.IsCounted());
      msg.Make(shm, head, body);
      assert(msg.valid());
      DEFER1(msg.Release(shm););

      for (uint64_t i = 0; i < n; ++i) {
         mq.Send(id, msg, timeout);
         while (!mq.TrySend(id, msg)) {}
      }
   };
   auto Reader = [&](int reader_id, std::atomic<bool> *run, bool isfork) {