我已经排除了UIViewControllerRepresentable的其他协议存根以缩短此代码，但此代码仅在尝试上传到Apple Connect时才会出错。
资产验证失败（50）应用引用Payload/some/path中的非公共选择器：volumeChanged：（ID：060de305-b6d2-4314-a238-c679fa85404e）
为什么volumeChanged函数不是公共选择器？

import SwiftUI
import AVFoundation
import MediaPlayer

struct VolumeEventReader<Content: View>: UIViewControllerRepresentable {
    class Coordinator: NSObject {
        var parent: VolumeEventReader
        var lastVolumeNotificationSequenceNumber: Int?
        var currentVolume = AVAudioSession.sharedInstance().outputVolume

        init(_ parent: VolumeEventReader) {
            self.parent = parent
        }

        @objc func volumeChanged(_ notification: NSNotification) {
            DispatchQueue.main.async { [self] in
                volumeControl(notification)
            }
        }

        func manageVolume(volume: Float, minVolume: Float) {
            switch volume {
            case minVolume: do {
                currentVolume = minVolume + 0.0625
            }
            case 1: do {
                currentVolume = 0.9375
            }
            default: break
            }

            parent.updateUIView(volume: volume)
            
            currentVolume = volume
        }

        func volumeControl(_ notification: NSNotification) {
            let minVolume: Float = 0.0625

            if let volume = notification.userInfo!["Volume"] as? Float {
                //avoiding duplicate events if same ID notification was generated
                if let seqN = self.lastVolumeNotificationSequenceNumber {
                    if seqN == notification.userInfo!["SequenceNumber"] as! Int {
                        // Duplicate nofification received
                    }
                    else {
                        self.lastVolumeNotificationSequenceNumber = (notification.userInfo!["SequenceNumber"] as! Int)
                        manageVolume(volume: volume, minVolume: minVolume)
                    }
                }
                else {
                    self.lastVolumeNotificationSequenceNumber = (notification.userInfo!["SequenceNumber"] as! Int)
                    manageVolume(volume: volume, minVolume: minVolume)
                }
            }
        }
    }

    func makeCoordinator() -> Coordinator {
        let coordinator = Coordinator(self)

        NotificationCenter.default.addObserver(
            coordinator,
            selector: #selector(Coordinator.volumeChanged),
            name: NSNotification.Name(rawValue: "SystemVolumeDidChange"),
            object: nil
        )

        return coordinator
    }
}