@Override
    public void rejectedExecution(final Runnable r, final ThreadPoolExecutor e) {
        LOG.error("Thread pool [{}] is exhausted! {}.", threadPoolName, e.toString());
    }
A handler for rejected tasks that silently discards the
rejected task.

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