code: func BootstrapKubeletConfigController(dynamicConfigDir string, transform dynamickubeletconfig.TransformFunc) (*kubeletconfiginternal.KubeletConfiguration, *dynamickubeletconfig.Controller, error) {
  	if !utilfeature.DefaultFeatureGate.Enabled(features.DynamicKubeletConfig) {
  		return nil, nil, fmt.Errorf("failed to bootstrap Kubelet config controller, you must enable the DynamicKubeletConfig feature gate")
  	}
  	if len(dynamicConfigDir) == 0 {
  		return nil, nil, fmt.Errorf("cannot bootstrap Kubelet config controller, --dynamic-config-dir was not provided")
  	}
  
  	// compute absolute path and bootstrap controller
  	dir, err := filepath.Abs(dynamicConfigDir)
  	if err != nil {
  		return nil, nil, fmt.Errorf("failed to get absolute path for --dynamic-config-dir=%s", dynamicConfigDir)
  	}
  	// get the latest KubeletConfiguration checkpoint from disk, or return the default config if no valid checkpoints exist
  	c := dynamickubeletconfig.NewController(dir, transform)
  	kc, err := c.Bootstrap()
  	if err != nil {
  		return nil, nil, fmt.Errorf("failed to determine a valid configuration, error: %v", err)
  	}
  	return kc, c, nil
  }
docs: // BootstrapKubeletConfigController constructs and bootstrap a configuration controller