Draw the contents of this to the given cairo context.
Typically, you'll use this function to implement fallback rendering of `GskRenderNode`s on an intermediate Cairo context, instead of using the drawing context associated to a [[email protected]]'s rendering buffer.
For advanced nodes that cannot be supported using Cairo, in particular for nodes doing 3D operations, this function may fail.
| this |
a `GskRenderNode` |
| cr |
cairo context to draw to |