code: def update(self, sent):
          
          self.offset = sent
  
          now = datetime.datetime.now()
  
          elapsed = (now - self.startTime).total_seconds()
          if elapsed > 0:
              mbps = (sent * 8 / (10 ** 6)) / elapsed
          else:
              mbps = None
  
          self._display(sent, now, self.name, mbps)
docs: Update self and parent with intermediate progress.