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"
		}
	}]
}
```

LAMBDA_EXECUTOR.cleanup(arn)
    try:
        arn_to_lambda.pop(arn)
    except KeyError:
        return not_found_error(func_arn(function))
    event_publisher.fire_event(event_publisher.EVENT_LAMBDA_DELETE_FUNC,
        payload={'n': event_publisher.get_hash(function)})
    i = 0
    while i < len(event_source_mappings):
        mapping = event_source_mappings[i]
        if mapping['FunctionArn'] == arn:
            del event_source_mappings[i]
            i -= 1
        i += 1
    result = {}
    return jsonify(result)
@app.route('%s/functions/<function>/code' % PATH_ROOT, methods=['PUT'])
def update_function_code(function):
    """ Update the code of an existing function
        ---
        operationId: 'updateFunctionCode'
        parameters:
            - name: 'request'
              in: body
    """
    data = json.loads(to_str(request.data))
    result = set_function_code(data, function)
    arn = func_arn(function)
    func_details = arn_to_lambda.get(arn)