Prepare the session, setting up the session object and loading in
        the values, assigning the IP address to the session if it's an new one.

def prepare(self):
        """Prepare the session, setting up the session object and loading in
        the values, assigning the IP address to the session if it's an new one.

        """
        super(SessionRequestHandler, self).prepare()
        result = yield gen.Task(self.start_session)
        LOGGER.debug('Exiting SessionRequestHandler.prepare: %r', result)