code: def pause_writing(self):
          '''Transport calls when the send buffer is full.'''
          if not self.is_closing():
              self._can_send.clear()
              self.transport.pause_reading(f pause_writing(self):
          '''Transport calls when the send buffer is full.'''
          if not self.is_closing():
              self._can_send.clear()
              self.transport.pause_reading()
docs: Transport calls when the send buffer is full.