Xamarin Center StackLayout within ScrollView
<p>I'm trying to horizontally center a <code>StackLayout</code> within a <code>ScrollView</code>.  However, the <code>StackLayout</code> isn't horizontally centered (it's left aligned). I tried centering the <code>ScrollView</code> but then the whole view is not scrollable - only the center section is.</p>

<pre><code>&lt;ScrollView BackgroundColor="Teal"&gt;
  &lt;StackLayout Spacing="5"
               Padding="30"
               WidthRequest="400"
               HorizontalOptions="Center"
               VerticalOptions="CenterAndExpand"
               BackgroundColor="Transparent"&gt;
       &lt;Label Text="Test"/&gt;
       &lt;Label Text="Test"/&gt;
       &lt;Label Text="Test"/&gt;
       &lt;Label Text="Test"/&gt;
  &lt;/StackLayout&gt;
&lt;/ScrollView&gt;
</code></pre>

<p>The centering works with 2 nested <code>StackLayout</code> elements, but it doesn't with the <code>ScrollView</code>. Any ideas?</p>