code: func (c *Client) PutDomain(dm *ct.DomainMigration) error {
  	if dm.Domain == "" {
  		return errors.New("controller: missing domain")
  	}
  	if dm.OldDomain == "" {
  		return errors.New("controller: missing old domain")
  	}
  	return c.Put("/domain", dm, dm)
  }
docs: // PutDomain migrates the cluster domain