title: Flutter webview intercept and add headers to all requests
body: <p>Using the webview_flutter package i could load my website and add session cookies to the initial URL.</p>
  
  <pre><code>_controller.future.then((controller) {
    _webViewController = controller;
    Map&lt;String, String&gt; header = {'Cookie': 'ci_session=${widget.sessionId}'};
    _webViewController.loadUrl('https://xxxx.com', headers: header);
  });
  </code></pre>
  
  <p>In order to keep the session going i need to add the same header for all requests not just for the initial one.
  Is there any way to intercept all requests and modify them by adding headers to them?</p>
  
  <p>the closest thing i found was <code>navigationDelegate</code>  but it only returns a <code>NavigationDecision</code> which isn't useful in my case.</p>