public ExecutorConfig setAllowCoreThreadTimeout(boolean allowCoreThreadTimeout) {
      this.allowCoreThreadTimeout = allowCoreThreadTimeout;
      return this;
    }
Allows timing out of core threads. Good to set this for non-critical thread pools for release
of unused resources. Refer to {@link ThreadPoolExecutor#allowCoreThreadTimeOut} for
additional details.
hbase-server/src/main/java/org/apache/hadoop/hbase/executor/ExecutorService.java