in src/main/java/software/amazon/qldb/QldbDriverImpl.java [85:102]
protected QldbDriverImpl(String ledgerName,
QldbSessionClient qldbSessionClient,
RetryPolicy retryPolicy,
int readAhead,
int maxConcurrentTransactions,
IonSystem ionSystem,
ExecutorService executorService) {
this.ledgerName = ledgerName;
this.amazonQldbSession = qldbSessionClient;
this.retryPolicy = retryPolicy;
this.ionSystem = ionSystem;
this.isClosed = new AtomicBoolean(false);
this.readAhead = readAhead;
this.executorService = executorService;
this.poolPermits = new Semaphore(maxConcurrentTransactions, true);
this.pool = new LinkedBlockingQueue<>();
}