code: func (m *metadata) InstanceID(ctx context.Context, name types.NodeName) (string, error) {
  	instanceID, err := m.get(metadataTypeInstanceID)
  	if err != nil {
  		return "", fmt.Errorf("could not get instance ID: %v", err)
  	}
  
  	zone, err := m.get(metadataTypeZone)
  	if err != nil {
  		return "", fmt.Errorf("could not get zone: %v", err)
  	}
  
  	return "/" + zone + "/" + instanceID, nil
  }
docs: // InstanceID returns the cloud provider ID of the specified instance.