docs: def next(self):
          """Iteration function.
  
          Note that it is possible to yield dangling ack packets as well, so user
          can detect if the sniffer missed the previous packet.
          """
  
          try:
              self._fetch()
              pkt = self.pkt_queue.popleft()
              try:
                  self._infer_acked(pkt)
              except:
                  pass
              try:
                  self._infer_retry(pkt)
              except:
                  pass
  
              return pkt
          except IndexError:
              raise StopIteration()