connect method

Implementation

@override
Future connect({Duration? timeout = const Duration(seconds: 5)}) async {
  if (Platform.isWindows) {
    if (_hPrinter != null) return;
    try {
      _hPrinter = _openWindowsPrinter();
    } catch (e) {
      _hPrinter = null;
      return Future.error(e.toString());
    }
  } else if (Platform.isAndroid) {
    if (_androidConnected) return;
    final vendorId = printer.vendorId;
    final productId = printer.productId;
    if (vendorId == null || productId == null) {
      return Future.error('USB printer has no vendorId/productId');
    }
    bool? ok;
    try {
      ok = await usbPrinter.connect(vendorId, productId);
    } catch (e) {
      return Future.error('Failed to connect USB printer: $e');
    }
    if (ok != true) {
      return Future.error(
          'Failed to connect USB printer ($vendorId:$productId)');
    }
    _androidConnected = true;
  }
}