code: private int[] decodeStart(BitArray row) throws NotFoundException {
      int endStart = skipWhiteSpace(row);
      int[] startPattern = findGuardPattern(row, endStart, START_PATTERN);
  
      // Determine the width of a narrow line in pixels. We can do this by
      // getting the width of the start pattern and dividing by 4 because its
      // made up of 4 narrow lines.
      this.narrowLineWidth = (startPattern[1] - startPattern[0]) / 4;
  
      validateQuietZone(row, startPattern[0]);
  
      return startPattern;
    }
docs: Identify where the start of the middle / payload section starts.
  
  @param row row of black/white values to search
  @return Array, containing index of start of 'start block' and end of
  'start block'