Serialize self to text stream.

        Matches convention of mongooplog.

def dump(self, stream):
        """Serialize self to text stream.

        Matches convention of mongooplog.
        """
        items = (
            ('time', self.time),
            ('inc', self.inc),
        )
        # use ordered dict to retain order
        ts = collections.OrderedDict(items)
        json.dump(dict(ts=ts), stream)