public void doTransform(ClassInfo classInfo) throws IOException, NotFoundException, CannotCompileException {
        if (!classInfo.getClassName().equals(TO_BE_TRANSFORMED_CLASS_NAME)) return;

        final CtClass ctClass = classInfo.getCtClass();
        final CtMethod method = ctClass.getDeclaredMethod(TO_BE_TRANSFORMED_METHOD);

        final String code = "$1 *= 2;";
        method.insertBefore(code);
        logger.info("[SampleExtensionTransformlet] insert code before method " + TO_BE_TRANSFORMED_METHOD
            + " of class " + method.getDeclaringClass().getName() + ": " + code);

        classInfo.setModified();
    }
{@link TtlTransformlet} for {@link ToBeTransformedClass}.

<B><I>Caution:</I></B><br>
MUST use string constant for class/method name!
<p>
MUST NOT use {@code Class<?> class = ToBeTransformedClass.class} to get the class to be transformed({@code ToBeTransformedClass}),
{@code ToBeTransformedClass.class} operation will force to load the class to be transformed,
and cause the Transformlet to <b>SKIP</b> the class transform!
ttl-integrations/sample-ttl-agent-extension-transformlet/src/main/java/com/alibaba/ttl/agent/extension_transformlet/sample/transformlet/SampleExtensionTransformlet.java