code: def _init(self, style, streamer, processors=None):
          
          self._stream = streamer
          if streamer.interactive:
              if streamer.supports_updates:
                  self.mode = "update"
              else:
                  self.mode = "incremental"
          else:
              self.mode = "final"
  
          if style and "width_" not in style and self._stream.width:
              style["width_"] = self._stream.width
          self._content = ContentWithSummary(
              StyleFields(style, processors or PlainProcessors()))
docs: Do writer-specific setup.
  
          Parameters
          ----------
          style : dict
              Style, as passed to __init__.
          streamer : interface.Stream
              A stream interface that takes __init__'s `stream` and `interactive`
              arguments into account.
          processors : field.StyleProcessors, optional
              A writer-specific processors instance.  Defaults to
              field.PlainProcessors().