ios - Alamofire - NetworkReachabilityManager doesn't work with .notReachable -

i have issue networkreachabilitymanager alamofire. tried test connection example code:

override func viewdidload() {     super.viewdidload()      let manager = networkreachabilitymanager(host: "www.apple.com")      manager?.listener = { status in      switch status {         case .notreachable:           print("network connection status - lost")       case .reachable(networkreachabilitymanager.connectiontype.ethernetorwifi):           print("network connection status - ethernet/wifi")       case .reachable(networkreachabilitymanager.connectiontype.wwan):           print("network connection status - wwan")       default:           break     }   }    manager?.startlistening() } 

when tried turn wifi off , received blank response. no response such "network connection status - lost".

but when tried turn on wifi , received result "network connection status - ethernet/wifi" in response. idea wrong .notreachable? suggestion appreciated.

according alamofire "make sure remember retain manager" create manager this

class a: uiviewcontroller{  let manager = networkreachabilitymanager(host: "www.apple.com")  override func viewdidload() { super.viewdidload()  // before start listening can check  if (manager?.isreachableonethernetorwifi == true)     {      print("internet available")     }     else     {     print("internet not available")     }  manager?.startlistening()  manager?.listener = { status in  switch status {     case .notreachable:       print("network connection status - lost")   case .reachable(networkreachabilitymanager.connectiontype.ethernetorwifi):       print("network connection status - ethernet/wifi")   case .reachable(networkreachabilitymanager.connectiontype.wwan):       print("network connection status - wwan")   default:       break            }     }       }  }