title: How to retrieve http header values from a WKWebView
body: <p>I have a <code>WKWebView</code> that enables users to login.  If they are successful I want to retrieve a userID, portalID and other information.  If the WebView downloads a JSON file with this information, how would I go about accessing it.  I know I can access http header information through the <code>WKNavigationDelegate</code>.  </p>