@Override
    public Set<String> getMapNames(final RefStreamDefinition refStreamDefinition) {
        Objects.requireNonNull(refStreamDefinition);
        return lmdbEnvironment.getWithReadTxn(readTxn ->
                mapDefinitionUIDStore.getMapNames(readTxn, refStreamDefinition));
    }
@return True if any {@link RefStreamDefinition}s have been loaded with this stream ID.
stroom-pipeline/src/main/java/stroom/pipeline/refdata/store/offheapstore/RefDataOffHeapStore.java