title: Graphql | Apollo client | How to change variables in existing subscription?
body: <p>I have setup a Apollo Server and Client with Subscriptions. Everything works as expected in basic setup. I am using Apollo Client's Subscribe method for subscription. Something like below:</p>
  
  <pre><code>graphqlClient.subscribe({ query, variables }).subscribe({
  next: d =&gt; {
    onData(d);
  },
  error: error =&gt; {
    handleErrorResponse(error).catch(e =&gt; {
      Logger.notifyError(new Error(`Real-time update error | ${e.message}.`));
    });
  }
  </code></pre>
  
  <p>});</p>
  
  <p>This works and I can see my onData callback firing on events. </p>
  
  <p>Question - In our application, the Subscription filter is dynamic and user can select different values which will impact the filter. I have gone through documentation and many (many) articles but could not find a way to update filters or how to handle this use case?</p>
  
  <p>Expectation - Once user selects any value and apply filter, I want to update my subscription on server to start using new filters? </p>