If you were hoping to have an easy solution to share your gaming on Twitch with the Xbox One, then you will have to wait until next year.
Microsoft confirmed to Engadget that the feature to stream you gaming exploits will not make the console launch and won't be in place until 2014 sometime. A little disappointing considering the PlayStation 4 can do it now. Twitch wasn't even originally mentioned as a streaming option for the PlayStation 4 and it has it working right off the bat.
For now you will have to use another piece of hardware such as a capture card from Hauppauge if you want to stream from the Xbox One. The Twitch app will be available though for you to watch from the console.