FCM Swift, payloads only received in foreground

Question

What code needs to be changed in order to allow the Swift FCM delegate code to receive payloads while the app is in the background? As an example I have started to use googles quickstart-ios projects for FCM. All certificates have been setup correctly and payloads are received while in foreground. The objective c codebase works in the foreground and background with no issue but I have not found a workable solution, (after a lot of looking), to make the Swift version work similarly.

I do have a nodejs server pushing the payloads to devices but to simplify for testing I am just using the Firebase Console messaging service. There are suggestions of solutions on other SO threads but none have worked. Most solutions I have seen involve payload priority or disabling method swizzling as referenced in this question. Unfortunately making those changes and setting the priority to high did not solve this problem for me. Any help would be greatly appreciated.

//
//  Copyright (c) 2016 Google Inc.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//

import UIKit
import UserNotifications

import Firebase
import FirebaseInstanceID
import FirebaseMessaging

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate {

  var window: UIWindow?

  func application(application: UIApplication,
                   didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {

    // [START register_for_notifications]
    if #available(iOS 10.0, *) {
      let authOptions : UNAuthorizationOptions = [.Alert, .Badge, .Sound]
      UNUserNotificationCenter.currentNotificationCenter().requestAuthorizationWithOptions(
        authOptions,
        completionHandler: {_,_ in })

      // For iOS 10 display notification (sent via APNS)
      UNUserNotificationCenter.currentNotificationCenter().delegate = self
      // For iOS 10 data message (sent via FCM)
      FIRMessaging.messaging().remoteMessageDelegate = self

    } else {
      let settings: UIUserNotificationSettings =
      UIUserNotificationSettings(forTypes: [.Alert, .Badge, .Sound], categories: nil)
      application.registerUserNotificationSettings(settings)
      application.registerForRemoteNotifications()
    }


    // [END register_for_notifications]

    FIRApp.configure()

    // Add observer for InstanceID token refresh callback.
    NSNotificationCenter.defaultCenter().addObserver(self,
        selector: #selector(self.tokenRefreshNotification),
        name: kFIRInstanceIDTokenRefreshNotification,
        object: nil)

    return true
  }

  // [START receive_message]
  func application(application: UIApplication, didReceiveRemoteNotification userInfo: [NSObject : AnyObject],
                   fetchCompletionHandler completionHandler: (UIBackgroundFetchResult) -> Void) {
    // If you are receiving a notification message while your app is in the background,
    // this callback will not be fired till the user taps on the notification launching the application.
    // TODO: Handle data of notification

    // Print message ID.
    print("Message ID: \(userInfo["gcm.message_id"]!)")

    // Print full message.
    print("%@", userInfo)
  }
  // [END receive_message]

  // [START refresh_token]
  func tokenRefreshNotification(notification: NSNotification) {
    if let refreshedToken = FIRInstanceID.instanceID().token() {
      print("InstanceID token: \(refreshedToken)")
    }

    // Connect to FCM since connection may have failed when attempted before having a token.
    connectToFcm()
  }
  // [END refresh_token]

  // [START connect_to_fcm]
  func connectToFcm() {
    FIRMessaging.messaging().connectWithCompletion { (error) in
      if (error != nil) {
        print("Unable to connect with FCM. \(error)")
      } else {
        print("Connected to FCM.")
      }
    }
  }
  // [END connect_to_fcm]

  func applicationDidBecomeActive(application: UIApplication) {
    connectToFcm()
  }

  // [START disconnect_from_fcm]
  func applicationDidEnterBackground(application: UIApplication) {
    FIRMessaging.messaging().disconnect()
    print("Disconnected from FCM.")
  }
  // [END disconnect_from_fcm]
}

// [START ios_10_message_handling]
@available(iOS 10, *)
extension AppDelegate : UNUserNotificationCenterDelegate {

  // Receive displayed notifications for iOS 10 devices.
  func userNotificationCenter(center: UNUserNotificationCenter,
                              willPresentNotification notification: UNNotification,
    withCompletionHandler completionHandler: (UNNotificationPresentationOptions) -> Void) {
    let userInfo = notification.request.content.userInfo
    // Print message ID.
    print("Message ID: \(userInfo["gcm.message_id"]!)")

    // Print full message.
    print("%@", userInfo)
  }
}

extension AppDelegate : FIRMessagingDelegate {
  // Receive data message on iOS 10 devices.
  func applicationReceivedRemoteMessage(remoteMessage: FIRMessagingRemoteMessage) {
    print("%@", remoteMessage.appData)
  }
}

// [END ios_10_message_handling]