}

    /**
     * Append newline to the message buffer.
     *
     * @return the current builder
     */
    @Nonnull
    default MessageBuilder newline() {
        return append(System.lineSeparator());
    }

    /**
     * Append formatted content to the buffer.
     * @see String#format(String, Object...)
     *
     * @param pattern a <a href="../util/Formatter.html#syntax">format string</a>