code: func Respond(status int, body interface{}) *NormalResponse {
  	var b []byte
  	var err error
  	switch t := body.(type) {
  	case []byte:
  		b = t
  	case string:
  		b = []byte(t)
  	default:
  		if b, err = json.Marshal(body); err != nil {
  			return Error(500, "body json marshal", err)
  		}
  	}
  	return &NormalResponse{
  		body:   b,
  		status: status,
  		header: make(http.Header),
  	}
  }
docs: // Respond create a response