Method called every time the rx_timer times out, due to the peer not
        sending a consecutive frame within the expected time window

def _rx_timer_handler(self):
        """Method called every time the rx_timer times out, due to the peer not
        sending a consecutive frame within the expected time window"""

        with self.rx_mutex:
            if self.rx_state == ISOTP_WAIT_DATA:
                # we did not get new data frames in time.
                # reset rx state
                self.rx_state = ISOTP_IDLE
                warning("RX state was reset due to timeout")