code: func (r *renoState) Update(packetsAcked int) {
  	if r.s.sndCwnd < r.s.sndSsthresh {
  		packetsAcked = r.updateSlowStart(packetsAcked)
  		if packetsAcked == 0 {
  			return
  		}
  	}
  	r.updateCongestionAvoidance(packetsAcked)
  }
docs: // Update updates the congestion state based on the number of packets that
  // were acknowledged.
  // Update implements congestionControl.Update.