Normally S3 objects in localstack can be accessed via `http://localhost:4572/bucket/key`.

However, if the object is 7 MBs or larger, attempting to access it via this URL will result in a 403 error. Objects any smaller are retrieved as expected.

(Possibly related: Lambda response size is limited to 6MB. Perhaps that is being used by accident?)
records = []
        i = 0
        for table_name in sorted(data['RequestItems'].keys()):
            for request in data['RequestItems'][table_name]:
                put_request = request.get('PutRequest')
                if put_request:
                    existing_item = self._thread_local('existing_items')[i]
                    keys = dynamodb_extract_keys(item=put_request['Item'], table_name=table_name)
                    if isinstance(keys, Response):
                        return keys
                    new_record = clone(record)
                    new_record['eventName'] = 'INSERT' if not existing_item else 'MODIFY'
                    new_record['dynamodb']['Keys'] = keys
                    new_record['dynamodb']['NewImage'] = put_request['Item']
                    if existing_item:
                        new_record['dynamodb']['OldImage'] = existing_item
                    new_record['eventSourceARN'] = aws_stack.dynamodb_table_arn(table_name)
                    records.append(new_record)
                delete_request = request.get('DeleteRequest')
                if delete_request:
                    keys = delete_request['Key']
                    if isinstance(keys, Response):
                        return keys
                    new_record = clone(record)
                    new_record['eventName'] = 'REMOVE'