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"
		}
	}]
}
```

save_file(tmp_file, zip_file_content)
    TMP_FILES.append(tmp_dir)
    lambda_details.cwd = tmp_dir
    return tmp_dir
def set_function_code(code, lambda_name, lambda_cwd=None):
    def generic_handler(event, context):
        raise ClientError(('Unable to find executor for Lambda function "%s". Note that ' +
            'Node.js, Golang, and .Net Core Lambdas currently require LAMBDA_EXECUTOR=docker') % lambda_name)
    arn = func_arn(lambda_name)
    lambda_details = arn_to_lambda[arn]
    runtime = lambda_details.runtime
    lambda_environment = lambda_details.envvars
    handler_name = lambda_details.handler or LAMBDA_DEFAULT_HANDLER
    code_passed = code
    code = code or lambda_details.code
    is_local_mount = code.get('S3Bucket') == BUCKET_MARKER_LOCAL
    zip_file_content = None
    if code_passed:
        lambda_cwd = lambda_cwd or set_archive_code(code_passed, lambda_name)
        if not is_local_mount:
            
            zip_file_content = get_zip_bytes(code_passed)
    else:
        lambda_cwd = lambda_cwd or lambda_details.cwd
    
    tmp_file = '%s/%s' % (lambda_cwd, LAMBDA_ZIP_FILE_NAME)
    if not zip_file_content:
        zip_file_content = load_file(tmp_file, mode='rb')
    
    lambda_handler = generic_handler