UMat.empty constructor
      
      UMat.empty({ 
    
- UMatUsageFlags flags = UMatUsageFlags.USAGE_DEFAULT,
create an empty UMat
Implementation
factory UMat.empty({UMatUsageFlags flags = UMatUsageFlags.USAGE_DEFAULT}) {
  final p = calloc<cvg.UMat>();
  cvRun(() => ccore.cv_UMat_create_1(flags.value, p));
  return UMat._(p);
}