code: func (ps *PassState) MarshalJSON() ([]byte, error) {
  	additionalParams := make(map[string]interface{})
  	if ps.ResultPath != "" {
  		additionalParams["ResultPath"] = ps.ResultPath
  	}
  	if ps.Result != nil {
  		additionalParams["Result"] = ps.Result
  	}
  	return ps.marshalStateJSON("Pass", additionalParams)
  }
docs: // MarshalJSON for custom marshalling