Real SQS throws `There should be at least one SendMessageBatchRequestEntry in the request. (Service: AmazonSQS; Status Code: 400; Error Code: AWS.SimpleQueueService.EmptyBatchRequest;` when there is a send batch of zero size.

This would be useful to mimic inside localstack in order to find these bugs earlier.
if method == 'OPTIONS' and path == '/':
            
            return 200
        if method != 'POST':
            return
        region_name = aws_stack.get_region()
        req_data = urlparse.parse_qs(to_str(data))
        action = req_data.get('Action', [None])[0]
        content_str = content_str_original = to_str(response.content)
        if response.status_code >= 400: