private EffectiveMeta buildEffectiveMeta(final long id, final long effectiveMs) {
        return new EffectiveMeta(id, "DUMMY_FEED", "DummyType", effectiveMs);
    }
Make sure that it copes with a map not being in an early stream but is in a later one.
stroom-app/src/test/java/stroom/pipeline/refdata/TestReferenceData.java