title: How to keep track of online users in GraphQL using GraphQL-Java-Kickstart
body: <p>Currently I am using <code>ApolloSubscriptionConnectionListener</code>.</p>
  
  <p>It contains 4 methods: <code>onConnect</code>, <code>onTerminate</code>, <code>onStart</code> and <code>onStop</code>.</p>
  
  <p>However <code>onTerminate</code> did not fire when I close my client. <code>onStop</code> seems to fire every time the client canceled the subscription. How can I check that a user is online?</p>