code: protected String format(ChannelHandlerContext ctx, String eventName) {
          String chStr = ctx.channel().toString();
          return new StringBuilder(chStr.length() + 1 + eventName.length())
              .append(chStr)
              .append(' ')
              .append(eventName)
              .toString();
      }
docs: Formats an event and returns the formatted message.
  
  @param eventName the name of the event