Reachability.swift: Notification is only fired once.

import UIKit
import ReachabilitySwift

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, GIDSignInDelegate {

var window: UIWindow?
var reachability: Reachability!

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.
    window = UIWindow()
    reachability = Reachability.init()

    NotificationCenter.default.addObserver(self, selector: #selector(reachabilityChanged),name: ReachabilityChangedNotification, object: nil)

    do {
        try reachability!.startNotifier()
    } catch {
        print("could not start reachability notifier")
    }

    return true
}

func reachabilityChanged() {
    DispatchQueue.main.async {
        //self.networkStatusChanged()
        print(self.reachability.currentReachabilityStatus)
    }
}

}