scan method
Implementation
@override
void scan(Function(List<ScanResult>) onScanResult) {
FlutterBluePlus.cancelWhenScanComplete(FlutterBluePlus.scanResults.listen(onScanResult));
FlutterBluePlus.startScan(
withServices: [Guid(btTimerServiceUuid)],
timeout: const Duration(seconds: 5));
}