@Override
    public void onShutdown() {
        if (LOG.isInfoEnabled()) {
            LOG.info("Task handler on shutdown: {}.", Thread.currentThread().getName());
        }
    }
Callback interface to be implemented for processing events
as they become available in the RingBuffer.

@author jiachun.fjc
jraft-rheakv/rheakv-core/src/main/java/com/alipay/sofa/jraft/rhea/util/concurrent/disruptor/TaskHandler.java