title: zxing flashlight not displaying on UI
body: <p>I am using Zxing barcode scanner in my PCL in Xamarin Form. The Issue is flashlight ON/Off option is not displaying on UI. This is very important for me to provide this option to the user.</p>
  
  <pre><code>           zxing = new ZXingScannerView
                  {
                      VerticalOptions = LayoutOptions.CenterAndExpand,
                      HorizontalOptions = LayoutOptions.FillAndExpand,
                      HeightRequest = 400,
                      AutomationId = "zxingScannerView",
                      IsTorchOn = true,
  
  
                  };
  
                  string _BarCode = "";
                  int _CountItems = 0;
                  int _scannedItem = 0;
                  zxing.OnScanResult += (result) =&gt;
                      Device.BeginInvokeOnMainThread(async () =&gt;
                      {
                   // doing something that i want with scan result
  
                  });
                  overlay = new ZXingDefaultOverlay
                    {
  
                     ShowFlashButton = true,
                      AutomationId = "zxingDefaultOverlay",
  
                  };
                  overlay.HeightRequest = 2;
                  overlay.BindingContext = this;
                  overlay.FlashButtonClicked += (sender, e) =&gt;
                  {
                      zxing.IsTorchOn = !zxing.IsTorchOn;
                  };
  </code></pre>
  
  <p>In Assambly info i have already added this line of code</p>
  
  <pre><code>[assembly: UsesPermission(Android.Manifest.Permission.Flashlight)]
  </code></pre>
  
  <p>Can you please tell me what mistake i did in my code. Thanks for comments and suggestions </p>