code: func (d *Deployment) set(meta *discoverd.ServiceMeta, deploymentMeta DeploymentMeta) error {
  	data, err := json.Marshal(deploymentMeta)
  	if err != nil {
  		return err
  	}
  	meta.Data = data
  	return d.service.SetMeta(meta)
  }
docs: // set updates the service metadata given the current version and the updated version
  // will return err if the current version is no longer current (performs CaS)