in src/main/java/org/apache/maven/shared/io/logging/DefaultMessageHolder.java [243:270]
        public CharSequence render() {
            StringBuffer buffer = new StringBuffer();
            if (onDemandSink == null) {
                buffer.append('[')
                        .append(MessageLevels.getLevelLabel(messageLevel))
                        .append("] ");
            }
            if (message != null && message.length() > 0) {
                buffer.append(message);
                if (error != null) {
                    buffer.append('\n');
                }
            }
            if (error != null) {
                buffer.append("Error:\n");
                StringWriter sw = new StringWriter();
                PrintWriter pw = new PrintWriter(sw);
                error.printStackTrace(pw);
                buffer.append(sw.toString());
            }
            return buffer;
        }