code: func (p *PrrSender) OnPacketLost(priorInFlight protocol.ByteCount) {
  	p.bytesSentSinceLoss = 0
  	p.bytesInFlightBeforeLoss = priorInFlight
  	p.bytesDeliveredSinceLoss = 0
  	p.ackCountSinceLoss = 0
  }
docs: // OnPacketLost should be called on the first loss that triggers a recovery
  // period and all other methods in this class should only be called when in
  // recovery.