public void close() {
            try {
                executor.shutdown();
                executor.awaitTermination(5, TimeUnit.SECONDS);
            } catch (InterruptedException e) {
                //
            } finally {
                executor.shutdownNow();
            }
        }
Synchronously shuts down and waits for enqueued entries to be sent.
container-search/src/main/java/com/yahoo/search/logging/AbstractThreadedLogger.java