I have a setup where there is a node.js application that writes to a kinesis stream using putRecords for two items. The kinesis stream feeds a Lambda function that is configured with an eventSourceMapping with a batch size of 1. However, when I debug what the Records Kinesis feeds the lambda for an invocation, I see that the lambda is processing two records. Both of these records are on the same shard and have a sequence number which is pretty close.

The interesting thing is that if I switch the node.js published to use putRecord instead of putRecords, the kinesis records have a slightly farther apart sequence number and the lambda is fed the records individually.

The java code to configure the event source mapping
```
        AWSLambdaAsync lambdaClient = AWSResourceFactory.getLambdaClient();
        CreateEventSourceMappingRequest request = new CreateEventSourceMappingRequest();
        request.setEventSourceArn(kinesisArn);
        request.setFunctionName(functionName);
        request.setEnabled(true);
        request.setStartingPosition(EventSourcePosition.TRIM_HORIZON);
        request.setBatchSize(1);
        lambdaClient.createEventSourceMapping(request);
```

The localstack lambda output that shows multiple records being read at a time:

```
{
	"Records": [{
		"eventID": "shardId-000000000000:49593014281924840790139112603493819506073986345293840386",
		"eventSourceARN": "arn:aws:kinesis:us-east-1:000000000000:stream/MyStream",
		"kinesis": {
			"partitionKey": "ed0f756b97234f4fae9e3d1a886b8fbc",
			"data": "myData1",
			"sequenceNumber": "49593014281924840790139112603493819506073986345293840386"
		}
	}, {
		"eventID": "shardId-000000000000:49593014281924840790139112603495028431893600974468546562",
		"eventSourceARN": "arn:aws:kinesis:us-east-1:000000000000:stream/MyStream",
		"kinesis": {
			"partitionKey": "abee63a9299385699d65e89a290a9065",
			"data": "myData2",
			"sequenceNumber": "49593014281924840790139112603495028431893600974468546562"
		}
	}]
}
```

'Records': []
            }
            for rec in records:
                event['Records'].append({
                    'eventID': 'shardId-000000000000:{0}'.format(rec['sequenceNumber']),
                    'eventSourceARN': stream_arn,
                    'kinesis': rec
                })
            run_lambda(event=event, context={}, func_arn=arn)
    except Exception as e:
        LOG.warning('Unable to run Lambda function on Kinesis records: %s %s' % (e, traceback.format_exc()))
def process_sqs_message(message_body, message_attributes, queue_name, region_name=None):
    
    try:
        region_name = region_name or aws_stack.get_region()
        queue_arn = aws_stack.sqs_queue_arn(queue_name, region_name=region_name)
        sources = get_event_sources(source_arn=queue_arn)
        arns = [s.get('FunctionArn') for s in sources]
        LOG.debug('Found %s source mappings for event from SQS queue %s: %s' % (len(arns), queue_arn, arns))
        source = next(iter(sources), None)
        if not source:
            return False
        if source:
            arn = source['FunctionArn']
            event = {'Records': [{
                'body': message_body,
                'receiptHandle': 'MessageReceiptHandle',
                'md5OfBody': md5(message_body),
                'eventSourceARN': queue_arn,
                'eventSource': 'aws:sqs',