scan method
Scan documents.
Implementation
scan(String config) {
if (_webTwain != null) {
_webTwain!.OpenSource();
_webTwain!.AcquireImage(parse(config), allowInterop(() {
_webTwain!.CloseSource();
}), allowInterop((settings, errCode, errString) {
_webTwain!.CloseSource();
print(errString);
}));
}
}