Xamarin Forms - Floating Bottom Right Button

BottomRightButton.xaml

<ContentPage.Content>
        <AbsoluteLayout>
            <StackLayout Orientation="Vertical" Spacing="0" AbsoluteLayout.LayoutFlags="All"
                         AbsoluteLayout.LayoutBounds="0,0,1,1">
                <!-- Other controls here. -->
            </StackLayout>
            <Button 
                x:Name="addButton"
                HorizontalOptions="End"
                VerticalOptions="End"
                WidthRequest="30"
                HeightRequest="30"
                CornerRadius="15"
                Text="+"
                Clicked="addButton_Clicked"
                AbsoluteLayout.LayoutFlags="PositionProportional"
                AbsoluteLayout.LayoutBounds="1, 1, AutoSize, AutoSize"
                Margin = "5,5"/>
        </AbsoluteLayout>
    </ContentPage.Content>
</ContentPage>