@Override
    public void onEvent(final MessageEvent<Runnable> event) throws Exception {
        event.getMessage().run();
        event.reset();
    }
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