code: func (instance *ApplicationInstance) UnmarshalJSON(data []byte) error {
  	var ccInstance struct {
  		Details string  `json:"details"`
  		Since   float64 `json:"since"`
  		State   string  `json:"state"`
  	}
  	err := cloudcontroller.DecodeJSON(data, &ccInstance)
  	if err != nil {
  		return err
  	}
  
  	instance.Details = ccInstance.Details
  	instance.State = constant.ApplicationInstanceState(ccInstance.State)
  	instance.Since = ccInstance.Since
  
  	return nil
  }
docs: // UnmarshalJSON helps unmarshal a Cloud Controller application instance
  // response.