code: func NewJsonResult(data string, exps ...time.Time) *JsonResult {
  	exp := time.Time{}
  	switch l := len(exps); {
  	case l == 1:
  		exp = exps[0]
  	case l > 1:
  		panic("too many exps")
  	}
  	return &JsonResult{
  		Object:     data,
  		Size:       uint32(len(data)),
  		Expiration: google_pb.NewTimestamp(exp),
  	}
  }
docs: // NewJsonResult creates a new JsonResult object with optional expiration time.