code: protected String formatByteBufHolder(String eventName, ByteBufHolder msg) {
      return formatByteBuf(eventName, msg.content());
    }
docs: Returns a String which contains all details to log the {@link ByteBufHolder}.
  <p>
  By default this method just delegates to {@link #formatByteBuf(String, ByteBuf)},
  using the content of the {@link ByteBufHolder}. Sub-classes may override this.