private OffsetSync[] createInitialSyncs(OffsetSync firstSync) {
        OffsetSync[] syncs = new OffsetSync[SYNCS_PER_PARTITION];
        clearSyncArray(syncs, firstSync);
        return syncs;
    }
Start the OffsetSyncStore, blocking until all previous Offset Syncs have been read from backing storage.
connect/mirror/src/main/java/org/apache/kafka/connect/mirror/OffsetSyncStore.java