code: public synchronized PacketBuilder withString(final String s)
      {
          try
          {
              withBytes(s.getBytes("utf-8"));
          }
          catch (final UnsupportedEncodingException e)
          {
              logger.error("UTF-8 encoding is not supported");
          }
  
          return this;
      }
docs: Adds a String
  @param s UTF-8 String
  @throws IllegalStateException see {@link #checkBuilt()}