public override async void OnPageFinished(Android.Webkit.WebView view, string url)
            {
                try
                {
                    _webView = view;
                    if (_extWebView != null)
                    {
                        view.Settings.JavaScriptEnabled = true;
                        await Task.Delay(100);

                        var result = await _extWebView.EvaluateJavaScriptAsync("(function(){return document.body.scrollHeight;})()");

                        if (int.TryParse(result, out var height))
                        {
                            _extWebView.HeightRequest = height + 30;
                        }
                        else
                        {
                            _extWebView.HeightRequest = view.ContentHeight;
                        }
                        view.EvaluateJavascript(_javascript, null);
                    }
                    base.OnPageFinished(view, url);
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);
                }
            }
        private async Task OnInjectJavascript(string script)
        {
            valueCallback.ResetValue();

            webView.EvaluateJavascript(script, valueCallback);

            await Task.Run(() =>
            {
                while (valueCallback.Value == null)
                {
                }
            });
        }