code: public StringBuilder appendPrintfOptions(StringBuilder out) {
      if (!isDefault()) {
        // Knock out the upper-case flag because that does not correspond to an options character.
        int optionFlags = flags & ~FLAG_UPPER_CASE;
        for (int bit = 0; (1 << bit) <= optionFlags; bit++) {
          if ((optionFlags & (1 << bit)) != 0) {
            out.append(FLAG_CHARS_ORDERED.charAt(bit));
          }
        }
        if (width != UNSET) {
          out.append(width);
        }
        if (precision != UNSET) {
          out.append('.').append(precision);
        }
      }
      return out;
    }
docs: Appends the data for this options instance in a printf compatible form to the given buffer.
  This method neither appends the leading {@code %} symbol nor a format type character. Output is
  written in the form {@code [width][.precision][flags]} and for the default instance, nothing is
  appended.
  
  @param out The output buffer to which the options are appended.