code: def _sync_io(self):
          
          if self._file_epoch == self.file_object.epoch:
              return
  
          if self._io.binary:
              contents = self.file_object.byte_contents
          else:
              contents = self.file_object.contents
  
          self._set_stream_contents(contents)
          self._file_epoch = self.file_object.epoch
docs: Update the stream with changes to the file object contents.