docs: public final Collection<TotalOrderLatch> notifyStateTransferStart(int topologyId, boolean isRebalance) {
        if (stateTransferInProgress.get() != null) {
           return Collections.emptyList();
        }
        List<TotalOrderLatch> preparingTransactions = new ArrayList<>(keysLocked.size());
        preparingTransactions.addAll(keysLocked.values());
        if (isRebalance) {
           stateTransferInProgress.set(new TotalOrderLatchImpl("StateTransfer-" + topologyId));
        }
        if (trace) {
           log.tracef("State Transfer start. It will wait for %s", preparingTransactions);
        }
        return preparingTransactions;
     }