@Override
        public byte[] doInTransform(Instrumentor instrumentor, ClassLoader classLoader, String className, Class<?> classBeingRedefined, ProtectionDomain protectionDomain, byte[] classfileBuffer) throws InstrumentException {
            InstrumentClass target = instrumentor.getInstrumentClass(classLoader, className, classfileBuffer);
            InstrumentMethod setPattern = target.getDeclaredMethod("setPattern", "java.lang.String");
            if (setPattern == null) {
                return null;
            }
            setPattern.addScopedInterceptor(PatternLayoutInterceptor.class, "ModifyPattern");
            return target.toBytecode();
        }
This modifier support slf4j 1.4.1 version and logback 0.9.8 version, or greater.
Because package name of MDC class is different on under those version 
and under those version is too old.
By the way slf4j 1.4.0 version release on May 2007.
Refer to url http://mvnrepository.com/artifact/org.slf4j/slf4j-api for detail.

@author minwoo.jung
@author yjqg6666
agent-module/plugins/logback/src/main/java/com/navercorp/pinpoint/plugin/logback/LogbackPlugin.java