Maps this Pair with *f*'; see :meth:`vanilla.core.Recver.map`

        Returns a new Pair of our current Sender and the mapped target's
        Recver.

def map(self, f):
        """
        Maps this Pair with *f*'; see :meth:`vanilla.core.Recver.map`

        Returns a new Pair of our current Sender and the mapped target's
        Recver.
        """
        return self._replace(recver=self.recver.map(f))