public static long truncateLastAccessTime(final long timeMs) {
        final long buckets = timeMs / PROCESSING_INFO_TRUNCATION_UNIT_MS;
        return buckets * PROCESSING_INFO_TRUNCATION_UNIT_MS;
    }
@return The time an entry for the associated ref stream definition was accessed,
truncated to the nearest PROCESSING_INFO_TRUNCATION_UNIT.
stroom-pipeline/src/main/java/stroom/pipeline/refdata/store/RefDataProcessingInfo.java