if #available(iOS 10.0, *) {
    let authOptions: UNAuthorizationOptions = [.alert, .badge, .sound]
    UNUserNotificationCenter.current().requestAuthorization(
        options: authOptions,
        completionHandler: {_, _ in }
    )

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

}
else {
    let settings: UIUserNotificationSettings = UIUserNotificationSettings(types: [.alert, .badge, .sound], categories: nil)
    application.registerUserNotificationSettings(settings)
}

将委托设置为self时出错。“FIRMessing没有成员remoteMessageDelegate”