private Runnable coreThread() {
        return () -> {
            Thread.currentThread().setName("offset-manager-core");
            while (isRunnable()) {
                try {
                    AgentUtils.silenceSleepInMs(CORE_THREAD_SLEEP_TIME);
                    cleanDbInstance();
                    cleanDbOffset();
                } catch (Throwable ex) {
                    LOGGER.error("offset-manager-core: ", ex);
                    ThreadUtils.threadThrowableHandler(Thread.currentThread(), ex);
                }
            }
        };
    }
thread for core thread.

@return runnable profile.
inlong-agent/agent-core/src/main/java/org/apache/inlong/agent/core/task/OffsetManager.java