How to intercept the request that an WebView does on all platforms?

I'm making use of an API. I authenticate via that API with an access token that I send into the header. Now when I try to load some content into an HtmlWebViewSource, for instance an image, there is nothing loaded. This is because the request it does to the images, won't add any headers to the requests. The code I currently have is:

On my ViewModel:

    public class ArticleViewModel : BaseViewModel
        {

            private HtmlWebViewSource _body;

            public const string BodyPropertyName = "Body";
            public HtmlWebViewSource Body {
                get { return _body; }
                set { this.SetProperty(ref _body, value, BodyPropertyName); }
            }

        private async void ExecuteLoadArticleCommand(string id)
            {
           if (IsBusy)
                    return;

                IsBusy = true;

                try
                {

            var article = ""; // article.Body contains a long HTML string with img tags in it.

                   Body = new HtmlWebViewSource
                    {
                        Html = article.Body
                    };


                }
                catch (Exception exception)
                {
                    var page = new ContentPage();
                    page.DisplayAlert("Error", string.Format("{0}", exception.Message), "Ok");
                }

                IsBusy = false;
            }

    }

On my ArticleView, I got the following inialization of a WebView:

    private WebView GetArticleWebLayout()
            {

                var browser = new WebView();
                browser.SetBinding(WebView.SourceProperty, "Body");

                return browser;

            }

How to intercept the requests that the WebView does and add the headers to it?