How to use NetworkReachabilityManager in Alamofire

Here's my implementation. I use it in a singleton. Remember to hold on to the reachability manager reference.

let reachabilityManager = Alamofire.NetworkReachabilityManager(host: "www.apple.com")

func listenForReachability() {
    self.reachabilityManager?.listener = { status in
        print("Network Status Changed: \(status)")
        switch status {
        case .NotReachable:
            //Show error state
        case .Reachable(_), .Unknown:
            //Hide error state
        }
    }

    self.reachabilityManager?.startListening()
}

NetworkManager Class

class NetworkManager {

//shared instance
static let shared = NetworkManager()

let reachabilityManager = Alamofire.NetworkReachabilityManager(host: "www.google.com")

func startNetworkReachabilityObserver() {

    reachabilityManager?.listener = { status in
        switch status {

            case .notReachable:
                print("The network is not reachable")

            case .unknown :
                print("It is unknown whether the network is reachable")

            case .reachable(.ethernetOrWiFi):
                print("The network is reachable over the WiFi connection")

            case .reachable(.wwan):
                print("The network is reachable over the WWAN connection")

            }
        }

        // start listening
        reachabilityManager?.startListening()
   }
}

Start Network Reachability Observer

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

        // add network reachability observer on app start
        NetworkManager.shared.startNetworkReachabilityObserver()

        return true
    }
}

I found the answer myself i.e by just writing a listener with closure as mentioned below:

let net = NetworkReachabilityManager()

net?.listener = { status in
    if net?.isReachable ?? false {

    switch status {

    case .reachable(.ethernetOrWiFi):
        print("The network is reachable over the WiFi connection")

    case .reachable(.wwan):
        print("The network is reachable over the WWAN connection")

    case .notReachable:
        print("The network is not reachable")

    case .unknown :
        print("It is unknown whether the network is reachable")

    }
}

net?.startListening()