code: public DeltaCRLIndicatorExtension getDeltaCRLIndicatorExtension()
          throws IOException {
  
          Object obj = getExtension(PKIXExtensions.DeltaCRLIndicator_Id);
          return (DeltaCRLIndicatorExtension)obj;
      }
docs: return the DeltaCRLIndicatorExtension, if any.
  
  @returns DeltaCRLIndicatorExtension or null (if no such extension)
  @throws IOException on error