title: Frame corner radius not rounding corners on iOS
body: <p>I am trying to round the corners of a stack layout, it works on android but on iOS, they still appear square but it does display the Frame shadow</p>
  
  <p>My XAML is </p>
  
  <pre><code>&lt;ContentPage.Content&gt;
      &lt;StackLayout BackgroundColor="WHITE"&gt;
          &lt;ListView&gt;
              &lt;ListView.ItemTemplate&gt;
                  &lt;DataTemplate&gt;
                      &lt;ViewCell&gt;
                          &lt;StackLayout&gt;
                              &lt;Frame CornerRadius="10" Padding="0" Margin="10, 10, 10, 10"&gt;
                                  &lt;StackLayout&gt;
                                      . . .
                                  &lt;/StackLayout&gt;
                              &lt;/Frame&gt;
                          &lt;/StackLayout&gt;
                      &lt;/ViewCell&gt;
                  &lt;/DataTemplate&gt;
              &lt;/ListView.ItemTemplate&gt;
          &lt;/ListView&gt;
      &lt;/StackLayout&gt;
  &lt;/ContentPage.Content&gt;
  </code></pre>