code: public FormatStringBuffer format(char ch) {
  
          Format fmt = getFormat();
  
          if (fmt.type != CHAR) throw new IllegalArgumentException("Expected a char format");
  
          if ((fmt.flags & LEFT) != LEFT) while (--fmt.fieldWidth > 0)
              buffer.append(' ');
          buffer.append(ch);
          while (--fmt.fieldWidth > 0)
              buffer.append(' ');
  
          return this;
      }
docs: Format a <tt>char</tt>.