DataScannerViewController could not get torch on when scanning.

I use DataScannerViewController to scan barcode and text recognize, and then get the AVCaptureDevice to use torch on/off, but DataScannerViewController will stop scanning. DataScannerViewController has no related API to get AVCaptureDevice to use torch. Expected: Could use AVCaptureDevice to turn on/off torch, at the same time DataScannerViewController could scan.