Core/Zmq: Added 50ms wait in the Run() loop to get rid of excessive cpu usage

(cherry picked from commit cbb6ca0339)

src/server/ipc/ZmqMux.cpp

@@ -56,6 +56,7 @@ void ZmqMux::Run()
 {
     for (;;)
     {
+        std::this_thread::sleep_for(std::chrono::milliseconds(50));
         if (!_poller->poll())
             break;