Bytes uploaded of the file so far.

        Note that we only have the file size if the file was requested directly,
        not if it's part of a folder listing.

def size(self):
        """Bytes uploaded of the file so far.

        Note that we only have the file size if the file was requested directly,
        not if it's part of a folder listing.
        """
        if hasattr(self.f.latestRevision, 'size'):
            return int(self.f.latestRevision.size)
        return None