code: def update(self, **kwargs):
          
          data = kwargs.get('data')
          if data is not None:
              if (util.pd and isinstance(data, util.pd.DataFrame) and
                  list(data.columns) != list(self.data.columns) and self._index):
                  data = data.reset_index()
              self.verify(data)
              kwargs['data'] = self._concat(data)
              self._count += 1
          super(Buffer, self).update(**kwargs)
docs: Overrides update to concatenate streamed data up to defined length.