public long getLastFlushTime() {
            return lastFlushTime;
        }
Flush the buffers if bulk requests have not been indexed for the past {@link
ElasticSearchProperties#getAsyncBufferFlushTimeout()} seconds. This is to prevent data loss
in case the instance is terminated, while the buffer still holds documents to be indexed.
es6-persistence/src/main/java/com/netflix/conductor/es6/dao/index/ElasticSearchDAOV6.java