duckOthers Audio Session Interrupted by Remote Push Notification

问题

I have a workout app that plays short clips of sound every couple of seconds. I have background music enabled so that music from other apps can be played while working out. The problem arises when I get a remote push notification (in my case, Slack) that has a sound, which somehow cancels out my duckingOther audio session and the music from other apps becomes loud again.

Question - How do I reset my duckingOthers audiosession when the user gets this type of interruption?

I set the audio session by calling the below function in didFinishLaunchingWithOptions:

private func setupAudioSession(){
        do {
            try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback, with: [.mixWithOthers, .duckOthers, .interruptSpokenAudioAndMixWithOthers])
            print("AVAudioSession Category Playback OK")
            do {
                try AVAudioSession.sharedInstance().setActive(true)
                print("AVAudioSession is Active")
            } catch let error as NSError {
                print(error.localizedDescription)
            }
        } catch let error as NSError {
            print(error.localizedDescription)
        }
    }

I have tried treating this as a hard interruption (for example a phone call), but when trying to apply the techniques used for this type of interruption, it seems that remote push notifications pass through the cracks. Below is what I used from a different question to try and catch interruptions.

@objc func handleInterruption(notification: Notification) {
        guard let userInfo = notification.userInfo,
            let typeValue = userInfo[AVAudioSessionInterruptionTypeKey] as? UInt,
            let type = AVAudioSessionInterruptionType(rawValue: typeValue) else {
                return
        }
        if type == .began {
            // Interruption began, take appropriate actions
            print("interruption started")
        }
        else if type == .ended {
            if let optionsValue = userInfo[AVAudioSessionInterruptionOptionKey] as? UInt {
                let options = AVAudioSessionInterruptionOptions(rawValue: optionsValue)
                if options.contains(.shouldResume) {
                    // Interruption Ended - playback should resume
                    print("should resume playback")
                    setupAudioSession()
                } else {
                    // Interruption Ended - playback should NOT resume
                    print("should not resume playback")
                }
            }
        }
    }

func setupNotifications() {
        let notificationCenter = NotificationCenter.default
        notificationCenter.addObserver(self,
                                       selector: #selector(handleInterruption),
                                       name: .AVAudioSessionInterruption,
                                       object: nil)
    }

来源：https://stackoverflow.com/questions/49354199/duckothers-audio-session-interrupted-by-remote-push-notification