public int getReferenceCount() {
        return referenceCount;
    }
< typeId >< referenceCount >
< 1 byte >< 3 bytes >
<p>
referenceCount stored as a 3 byte unsigned integer so a max
of ~16 million.
stroom-pipeline/src/main/java/stroom/pipeline/refdata/store/offheapstore/ValueStoreMeta.java