Returns ``True`` if you can expect multiple chunks.

        NB: If a particular file representation is in memory, subclasses should
        always return ``False`` -- there's no good reason to read from memory in
        chunks.

def multiple_chunks(self, chunk_size=None):
        """
        Returns ``True`` if you can expect multiple chunks.

        NB: If a particular file representation is in memory, subclasses should
        always return ``False`` -- there's no good reason to read from memory in
        chunks.
        """
        if not chunk_size:
            chunk_size = self.DEFAULT_CHUNK_SIZE
        return self.size > chunk_size