Send a metric to Riemann.

def process(self, metric):
        """
        Send a metric to Riemann.
        """
        event = self._metric_to_riemann_event(metric)
        try:
            self.client.send_event(event)
        except Exception as e:
            self.log.error(
                "RiemannHandler: Error sending event to Riemann: %s", e)