Rx extension for CFNotification

RxCFNotification.swift

extension Reactive where Base: NSObject {
    func cfNotification(notificationName: CFString) -> Observable<Notification> {
        let cfNotificationName = CFNotificationName(notificationName)
        let notificationCenter = CFNotificationCenterGetDarwinNotifyCenter()
        CFNotificationCenterAddObserver(
            notificationCenter,
            Unmanaged.passRetained(self.base).toOpaque(),
            { (
                center: CFNotificationCenter?,
                observer: UnsafeMutableRawPointer?,
                name: CFNotificationName?,
                object: UnsafeRawPointer?,
                userInfo: CFDictionary?
                ) in
                if let name = name {
                    NotificationCenter.default.post(name: Notification.Name(name.rawValue as String), object: nil)
                }
        },
            notificationName,
            nil,
            CFNotificationSuspensionBehavior.deliverImmediately
        )
        return NotificationCenter.default.rx.notification(Notification.Name(notificationName as String))
            .do(onDispose: {
                CFNotificationCenterRemoveObserver(
                    notificationCenter,
                    Unmanaged.passRetained(self.base).toOpaque(),
                    cfNotificationName, nil
                )
        })
    }
}