How do I add built-in bar buttons?

So, I know how to add a ToolbarItem to my Pages and assign it an image, and I know how to assign an image to a Button. But is there any way to take advantage of the operating system built in buttons? How do I add, for example on iOS, the UIBarButtonSystemItem.Trash image to my Xamarin.Forms UI? I realize that this isn't exactly cross-platform, but if you can get to the built-in image, can you use it as an ImageSource in Forms somehow?