title: GraphQL endpoint for file download
body: <p>Is it possible to trigger a file download in a browser from the GraphQL endpoint on an <code>apollo-server-express</code> application?</p>
  
  <p>I have the endpoint written in a standard express <code>app.get</code> function (see below) but I would like to make use of the GraphQL context for file download and so I'm wondering if it's possible to cause a download from a GraphQL endpoint.</p>
  
  <p>Here's a bare-bones example of what I have on the express end in the <code>app.get</code> function:</p>
  
  <pre><code>app.get('/download-batch/:batchId', async (req, res) =&gt; {
    res.send(new Buffer('test'));
  });
  </code></pre>
  
  <p>Any help would me much appreciated. Thanks!</p>