docs: private static void percentEncode(Writer writer, char c, String characterEncoding) throws IOException
      {
          String app = null;
          if (c > (char)((short)0x007F))
          {
              //percent encode in the proper encoding to be consistent
              //app = percentEncodeNonUsAsciiCharacter(writer c, characterEncoding);
              percentEncodeNonUsAsciiCharacter(writer, c, characterEncoding);
          }
          else
          {
              //percent encode US-ASCII char (0x00-0x7F range)
              //app = "%" + HEX_CHARSET.charAt( ((c >> 0x4) % 0x10)) +HEX_CHARSET.charAt(c % 0x10);
              writer.write('%');
              writer.write(HEX_CHARSET.charAt( ((c >> 0x4) % 0x10)));
              writer.write(HEX_CHARSET.charAt(c % 0x10));
          }
          //return app;
      }