private void closeAndDeleteLegacyStore() {
        try {
            closeAndDeleteStore(legacyRefDataStore);
        } finally {
            this.legacyRefDataStore = null;
            migrationCheckRequired = false;
        }
    }
@return The count of feed stores initialised, 1 or 0.
stroom-pipeline/src/main/java/stroom/pipeline/refdata/store/offheapstore/DelegatingRefDataOffHeapStore.java