@Override
    public void stop() throws Exception {
        LOGGER.info("Shutting down entry eviction timer");
        try {
            timer.cancel();
        } catch (Exception e) {
            LOGGER.error("Error shutting down the timer: {}", LogUtil.exceptionMessage(e), e);
        }
    }
@return An optional containing a non-blank attribute value, else empty.
stroom-receive/stroom-receive-common/src/main/java/stroom/receive/common/DataFeedKeyServiceImpl.java