Update parameters for selected dataframe after a completed batch
        Parameters
        ----------
        dataframe : pandas.DataFrame
            Selected dataframe needs to be modified.

def _process_batch(self, param, dataframe):
        """Update parameters for selected dataframe after a completed batch
        Parameters
        ----------
        dataframe : pandas.DataFrame
            Selected dataframe needs to be modified.
        """
        now = time.time()
        if param.eval_metric is not None:
            metrics = dict(param.eval_metric.get_name_value())
            param.eval_metric.reset()
        else:
            metrics = {}
        # #11504
        try:
            speed = self.frequent / (now - self.last_time)
        except ZeroDivisionError:
            speed = float('inf')
        metrics['batches_per_sec'] = speed * self.batch_size
        metrics['records_per_sec'] = speed
        metrics['elapsed'] = self.elapsed()
        metrics['minibatch_count'] = param.nbatch
        metrics['epoch'] = param.epoch
        self.append_metrics(metrics, dataframe)
        self.last_time = now