我在我的iPhone上发布了Airplay服务，但其他iOS设备无法检测到它

Question

我想为iOS设备编写一个Airplay接收器，这样我就可以将iPhone上的照片/视频分享给其他iOS设备。首先，我必须发布Airplay服务，并希望它可以被iPhone或iPad等其他iOS设备检测到。我写了一个发布服务的试点程序，遗憾的是其它iOS设备无法检测到它。我的代码有什么问题？

@IBAction func StartPublish(_ sender: UIButton)
{
    print("Start publishing...")

    if (airplayService == nil)
    {
        airplayService = NetService(domain: "", type: "_airplay._tcp.", name: "BaoWJ", port: 7000)
        airplayService.delegate = self

        let dataModel = "AppleTV2,1".data(using: String.Encoding.utf8)!
        let dataDeviceID = "DC:37:14:0C:6C:D6".data(using: String.Encoding.utf8)!
        let dataFeature = "0x39F7".data(using: String.Encoding.utf8)!
        let dataVer = "130.14".data(using: String.Encoding.utf8)!
        let txtAirplayDic = ["deviceid": dataDeviceID,
                             "features": dataFeature,
                             "model": dataModel,
                             "srcvers": dataVer
                            ]
        let txtAirplayData = NetService.data(fromTXTRecord: txtAirplayDic)
        airplayService.setTXTRecord(txtAirplayData)
    }
    airplayService.publish()

    if (raopService == nil)
    {
        raopService = NetService(domain: "", type: "_raop._tcp.", name: "DC37140C6CD6@BaoWJ", port: 45192)
        raopService.delegate = self

        let dataAM = "AppleTV2,1".data(using: String.Encoding.utf8)!
        let dataCH = "2".data(using: String.Encoding.utf8)!
        let dataCN = "0,1,2,3".data(using: String.Encoding.utf8)!
        let dataDA = "true".data(using: String.Encoding.utf8)!
        let dataET = "0,3,5".data(using: String.Encoding.utf8)!
        let dataFT = "0x39F7".data(using: String.Encoding.utf8)!
        let dataMD = "0,1,2".data(using: String.Encoding.utf8)!
        let dataPW = "false".data(using: String.Encoding.utf8)!
        let dataSV = "false".data(using: String.Encoding.utf8)!
        let dataSR = "44100".data(using: String.Encoding.utf8)!
        let dataSS = "16".data(using: String.Encoding.utf8)!
        let dataTP = "UDP".data(using: String.Encoding.utf8)!
        let dataVN = "65537".data(using: String.Encoding.utf8)!
        let dataVS = "130.14".data(using: String.Encoding.utf8)!
        let dataSF = "0x4".data(using: String.Encoding.utf8)!
        let txtRaopDic = ["am": dataAM,
                          "ch": dataCH,
                          "cn": dataCN,
                          "da": dataDA,
                          "et": dataET,
                          "ft": dataFT,
                          "md": dataMD,
                          "pw": dataPW,
                          "sv": dataSV,
                          "sr": dataSR,
                          "ss": dataSS,
                          "tp": dataTP,
                          "vn": dataVN,
                          "vs": dataVS,
                          "sf": dataSF
                         ]
        let txtRaopData = NetService.data(fromTXTRecord: txtRaopDic)
        raopService.setTXTRecord(txtRaopData)
    }
    raopService.publish()

}