Logic to let the plugin instance process the redis key/val
        Split out for unit testing

        @param instance: the plugin instance
        @param key: the redis key
        @param val: the key value from redis

def _process_key_val(self, instance, key, val):
        '''
        Logic to let the plugin instance process the redis key/val
        Split out for unit testing

        @param instance: the plugin instance
        @param key: the redis key
        @param val: the key value from redis
        '''
        if instance.check_precondition(key, val):
            combined = '{k}:{v}'.format(k=key, v=val)
            self._increment_total_stat(combined)
            self._increment_plugin_stat(
                instance.__class__.__name__,
                combined)
            instance.handle(key, val)
            self.redis_conn.delete(key)
            failkey = self._get_fail_key(key)
            if self.redis_conn.exists(failkey):
                self.redis_conn.delete(failkey)