docs: private void format(NumberFormat nf, StringBuilder buffer, double value, int maxIntegerDigits) {
      if(value >= 0) {
        buffer.append(" + ");
      }
      else {
        buffer.append(" - ");
      }
      int digits = maxIntegerDigits - integerDigits(value);
      for(int d = 0; d < digits; d++) {
        buffer.append(' ');
      }
      buffer.append(nf.format(Math.abs(value)));
    }