class TransactionIdTracker {

    public long newestEncounteredTxId()
    {
        // return the "last committed" because it is the newest id
        // "last closed" will return the last gap-free id, pottentially for some old transaction because there might be other committing transactions
        return transactionIdStore().getLastCommittedTransactionId();
    }

    public  TransactionIdTracker( Supplier<TransactionIdStore> transactionIdStoreSupplier, AvailabilityGuard databaseAvailabilityGuard );

}