code: func (kl *Kubelet) updatePodCIDR(cidr string) (bool, error) {
  	kl.updatePodCIDRMux.Lock()
  	defer kl.updatePodCIDRMux.Unlock()
  
  	podCIDR := kl.runtimeState.podCIDR()
  
  	if podCIDR == cidr {
  		return false, nil
  	}
  
  	// kubelet -> generic runtime -> runtime shim -> network plugin
  	// docker/non-cri implementations have a passthrough UpdatePodCIDR
  	if err := kl.getRuntime().UpdatePodCIDR(cidr); err != nil {
  		// If updatePodCIDR would fail, theoretically pod CIDR could not change.
  		// But it is better to be on the safe side to still return true here.
  		return true, fmt.Errorf("failed to update pod CIDR: %v", err)
  	}
  
  	klog.Infof("Setting Pod CIDR: %v -> %v", podCIDR, cidr)
  	kl.runtimeState.setPodCIDR(cidr)
  	return true, nil
  }
docs: // updatePodCIDR updates the pod CIDR in the runtime state if it is different
  // from the current CIDR. Return true if pod CIDR is actually changed.