code: @InternalApi
    int computeDeadlineSeconds() {
      int sec = ackLatencyDistribution.getPercentile(PERCENTILE_FOR_ACK_DEADLINE_UPDATES);
  
      // Use Ints.constrainToRange when we get guava 21.
      if (sec < Subscriber.MIN_ACK_DEADLINE_SECONDS) {
        sec = Subscriber.MIN_ACK_DEADLINE_SECONDS;
      } else if (sec > Subscriber.MAX_ACK_DEADLINE_SECONDS) {
        sec = Subscriber.MAX_ACK_DEADLINE_SECONDS;
      }
      return sec;
    }
docs: Compute the ideal deadline, set subsequent modacks to this deadline, and return it.