presto-kinesis/src/main/java/io/prestosql/plugin/kinesis/KinesisShardCheckpointer.java/KinesisShardCheckpointer/getLastReadSeqNumber
class KinesisShardCheckpointer:    public String getLastReadSeqNumber()
    {
        String lastReadSeqNumber = null;
        KinesisClientLease oldLease = null;
        if (currentIterationNumber > 0) {
            try {
                oldLease = leaseManager.getLease(createCheckpointKey(currentIterationNumber - 1));
            }
            catch (DependencyException | InvalidStateException | ProvisionedThroughputException e) {
                throwIfUnchecked(e);
                throw new RuntimeException(e);
            }
            if (oldLease != null) {
                // ExtendedSequenceNumber type in latest API:
                lastReadSeqNumber = oldLease.getCheckpoint().toString();
            }
        }
        if (lastReadSeqNumber == null) {
            log.info("Previous checkpoint not found. Starting from beginning of shard");
        }
        else {
            log.info("Resuming from " + lastReadSeqNumber);
        }
        return lastReadSeqNumber;
    }