code: def format_row_filter(self, next_filter):
          
          next(next_filter)
          while True:
              items = (yield)
              assert all(isinstance(x, VTMLBuffer) for x in items)
              raw = (fn(x) for x, fn in zip(items, self.formatters))
              for x in itertools.zip_longest(*raw):
                  next_filter.send(x)
docs: Apply overflow, justification, padding and expansion to a row.