IOS Swift 3 create URLSession extension for synchronous and asynchronous request -

hi every 1 i'm create extension urlsession in swift 3 create synchronous , asynchronous request. here implementation

extension urlsession {     func sendsynchronousrequest(request: url, completionhandler: @escaping (data?, urlresponse?, error?) -> void) {         let semaphore = dispatchsemaphore(value: 0)          let task = self.datatask(with: request) { (data, response, error) in             completionhandler(data,response,error)             semaphore.signal()         }         task.resume()         semaphore.wait(timeout: .distantfuture)     }      func sendasynchronousrequest(request: urlrequest, completionhandler: @escaping (data?, urlresponse?, error?) -> void) -> urlsessiondatatask {         let task = self.datatask(with: request) { data, response, error in             completionhandler(data, response, error)         }         task.resume()         return task     } } 

i have xcode suggest me insert @escaping function. don't know whether implementation correct

i have warning @ line

anyone know how correct extension? appreciate! thanks!

i found implementation in swift1/2 can't remember. not own. rewrote in swift3. can't remember found :/

func synchronousdatataskwithurl(url: url) -> (data?, urlresponse?, error?) {     var data: data?, response: urlresponse?, error: error?      let semaphore = dispatchsemaphore(value: 0)      datatask(with: url) {         data = $0; response = $1; error = $2         semaphore.signal()         }.resume()      semaphore.wait()      return (data, response, error) }