Add missing Buffer interface to io module.
Add missing Buffer interface to io module.

kuujo/copycat,atomix/atomix,arnonmoscona/copycat,madjam/copycat,aruanruan/copycat,arnonmoscona/copycat,tempbottle/copycat,aruanruan/copycat,kuujo/copycat,madjam/copycat,atomix/atomix,tempbottle/copycat