func tagsClientIfDefined(d *schema.ResourceData, meta interface{}) (*tags.RestClient, error) {
	old, new := d.GetChange(vSphereTagAttributeKey)
	if len(old.(*schema.Set).List()) > 0 || len(new.(*schema.Set).List()) > 0 {
		log.Printf("[DEBUG] tagsClientIfDefined: Loading tagging client")
		client, err := meta.(*VSphereClient).TagsClient()
		if err != nil {
			return nil, err
		}
		return client, nil
	}
	log.Printf("[DEBUG] tagsClientIfDefined: No tags configured, skipping loading of tagging client")
	return nil, nil
}
func tagsClientIfDefined(d *schema.ResourceData, meta interface{}) (*tags.RestClient, error) {
	old, new := d.GetChange(vSphereTagAttributeKey)
	if len(old.(*schema.Set).List()) > 0 || len(new.(*schema.Set).List()) > 0 {
		log.Printf("[DEBUG] tagsClientIfDefined: Loading tagging client")
		client, err := meta.(*VSphereClient).TagsClient()
		if err != nil {
			return nil, err
		}
		return client, nil
	}
	log.Printf("[DEBUG] tagsClientIfDefined: No tags configured, skipping loading of tagging client")
	return nil, nil
}
// tagsClientIfDefined goes through the client validation process and returns
// the tags client only if there are tags defined in the supplied ResourceData.
//
// This should be used to fetch the tagging REST client on resources that
// support tags, usually closer to the beginning of a CRUD function to check to
// make sure it's worth proceeding with most of the operation. The returned
// client should be checked for nil before passing it to processTagDiff.