Fixed topic gc bug

src/Http/Server.php

@@ -54,6 +54,9 @@ class Server
         $this->logger = $this->createLogger();
 
         $this->topicManager = new TopicManager();
+        $this->loop->addPeriodicTimer(30, function () {
+            $this->topicManager->garbageCollect();
+        });
         
         $this->webSocketClients = new SplObjectStorage();