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"
		}
	}]
}
```

return jsonify(do_update_alias(arn, name, version, description))
@app.route('%s/functions/<function>/aliases/<name>' % PATH_ROOT, methods=['GET'])
def get_alias(function, name):
    arn = func_arn(function)
    if arn not in arn_to_lambda:
        return not_found_error(arn)
    if name not in arn_to_lambda.get(arn).aliases:
        return not_found_error(msg='Alias not found: %s:%s' % (arn, name))
    return jsonify(arn_to_lambda.get(arn).aliases.get(name))
@app.route('%s/functions/<function>/aliases' % PATH_ROOT, methods=['GET'])
def list_aliases(function):
    arn = func_arn(function)
    if arn not in arn_to_lambda:
        return not_found_error(arn)
    return jsonify({'Aliases': sorted(arn_to_lambda.get(arn).aliases.values(),
                                      key=lambda x: x['Name'])})
@app.route('/<version>/functions/<function>/concurrency', methods=['PUT'])
def put_concurrency(version, function):
    
    
    
    arn = func_arn(function)
    data = json.loads(request.data)
    lambda_details = arn_to_lambda.get(arn)
    if not lambda_details:
        return not_found_error(arn)
    lambda_details.concurrency = data
    return jsonify(data)
@app.route('/<version>/tags/<arn>', methods=['GET'])
def list_tags(version, arn):