def make_big_empty_files(self):
        """
        Write out a empty file so the workers can seek to where they should write and write their data.
        """
        for file_url in self.file_urls:
            local_path = file_url.get_local_path(self.dest_directory)
            with open(local_path, "wb") as outfile:
                if file_url.size > 0:
                    outfile.seek(int(file_url.size) - 1)
                    outfile.write(b'\0')