public override void ViewWillLayoutSubviews()
{
    base.ViewWillLayoutSubviews();

    if (TabBar != null)
    {
        foreach (var item in TabBar.Items)
        {
            item.ImageInsets = new UIEdgeInsets(5, 0, -5, 0);
        }
    }
}

public MyTabbedPage()
{
    On<Android>().SetToolbarPlacement(ToolbarPlacement.Bottom);
}