ios9 - Swift: how to check for availability of protocols? -

since swift 2, there cleaner way check if class or property available:

@available(ios 8.0, *) var somevarhere = someclasshere() 

however, can't find anywhere how check protocol availability, e.g. sfsafariviewcontrollerdelegate. suggestions?

thanks @lu_, got solution: using extensions.

class viewcontroller: uiviewcontroller {      override func viewdidload() {         super.viewdidload()          if #available(ios 9, *) {             let sfc = sfsafariviewcontroller(url: nsurl(string: "http://www.google.bg")!)             sfc.delegate = self             presentviewcontroller(sfc, animated: true, completion: nil)         }     } }  @available(ios 9, *) extension viewcontroller: sfsafariviewcontrollerdelegate {     func safariviewcontrollerdidfinish(controller: sfsafariviewcontroller) {         controller.dismissviewcontrolleranimated(true, completion: nil)     } }