code: func (client *Client) UpdateApplicationEnvironmentVariables(appGUID string, envVars EnvironmentVariables) (EnvironmentVariables, Warnings, error) {
  	bodyBytes, err := json.Marshal(envVars)
  	if err != nil {
  		return EnvironmentVariables{}, nil, err
  	}
  
  	request, err := client.newHTTPRequest(requestOptions{
  		URIParams:   internal.Params{"app_guid": appGUID},
  		RequestName: internal.PatchApplicationEnvironmentVariablesRequest,
  		Body:        bytes.NewReader(bodyBytes),
  	})
  	if err != nil {
  		return EnvironmentVariables{}, nil, err
  	}
  
  	var responseEnvVars EnvironmentVariables
  	response := cloudcontroller.Response{
  		DecodeJSONResponseInto: &responseEnvVars,
  	}
  	err = client.connection.Make(request, &response)
  	return responseEnvVars, response.Warnings, err
  }
docs: // UpdateApplicationEnvironmentVariables adds/updates the user provided
  // environment variables on an application. A restart is required for changes
  // to take effect.