fix max listner warning

Author: Moumouls

src/Adapters/PubSub/EventEmitterPubSub.js

@@ -46,6 +46,10 @@ function createPublisher(): any {
 }
 
 function createSubscriber(): any {
+  // createSubscriber is called once at live query server start
+  // to avoid max listeners warning, we should clean up the event emitter
+  // each time this function is called
+  if (emitter) emitter.removeAllListeners();
   return new Subscriber(emitter);
 }