+ packet_rate = transmit_rate * self.ppta
+ # We have a float. TRex way of rounding it is not obvious.
+ # The biggest source of mismatch is Inter Stream Gap.
+ # So the code tolerates 10 usec of missing packets.
+ expected_attempt_count = (target_duration - 1e-5) * packet_rate
+ expected_attempt_count = math.ceil(expected_attempt_count)
+ # TRex can send more.
+ expected_attempt_count = max(expected_attempt_count, self._sent)
+ unsent = expected_attempt_count - self._sent
+ pass_count = self._received
+ fail_count = expected_attempt_count - pass_count