listenPrinterConnectState method Null safety

  1. @override
Stream<List<PrinterDevice>?> listenPrinterConnectState()
override

监听打印机连接状态

Implementation

@override
Stream<List<PrinterDevice>?> listenPrinterConnectState() {
  // TODO: implement listenPrinterConnectState
  throw UnimplementedError();
}