我可以在iOS的Core Text中使用NSAttributedString吗？

I'm trying to work out how to take an NSAttributedString and use it in Core Text on the iPad. I watched one of the WWDC videos (110) which has slides (but no source code) and it describes how to create an NSAttributedString, then just put it into a CTFramesetterRef:I'm trying to work out how to take an NSAttribu