title: Apollo Link response headers
body: <p>I am using the latest version of Apollo Client in a simple React app and I am trying to pull out a header value from the response that is being used to show the size of the record set being returned.</p>
  
  <p>I appreciate that this is not the most elegant way of providing the result set size, but that is how the API has currently been set up.</p>
  
  <p>I was hoping to use the the middleware type options to do this, but when I inspect the response object I can't seem to pull out any headers.</p>
  
  <p>The network trace does show that the response header is as expected so I suspect I am misunderstanding how to get at the underlying objects that I need.</p>
  
  <p>I have checked the documentation, but nothing stands out as obvious hence the question here ...</p>