@Override
    public String toString() {
        return "RefDataProcessingInfo{" +
                "createTimeEpochMs=" + Instant.ofEpochMilli(createTimeEpochMs).toString() +
                ", lastAccessedTimeEpochMs=" + Instant.ofEpochMilli(lastAccessedTimeEpochMs).toString() +
                ", effectiveTimeEpochMs=" + Instant.ofEpochMilli(effectiveTimeEpochMs).toString() +
                ", processingState=" + processingState +
                '}';
    }
@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