code: func (c *Verification) Control(m *VerifyControlRequest) (*VerifyControlResponse, error) {
  	if len(m.RequestID) == 0 {
  		return nil, errors.New("Invalid Request ID field specified")
  	}
  
  	if len(m.Command) == 0 {
  		return nil, errors.New("Invalid Command field specified")
  	}
  
  	var verifyControlResponse *VerifyControlResponse
  
  	if !c.client.useOauth {
  		m.apiKey = c.client.apiKey
  		m.apiSecret = c.client.apiSecret
  	}
  
  	var r *http.Request
  	buf, err := json.Marshal(m)
  	if err != nil {
  		return nil, errors.New("invalid message struct - unable to convert to JSON")
  	}
  
  	b := bytes.NewBuffer(buf)
  	r, err = http.NewRequest("POST", apiRootv2+"/verify/control/json", b)
  	if err != nil {
  		return nil, err
  	}
  
  	r.Header.Add("Accept", "application/json")
  	r.Header.Add("Content-Type", "application/json")
  
  	resp, err := c.client.HTTPClient.Do(r)
  	if err != nil {
  		return nil, err
  	}
  
  	defer resp.Body.Close()
  
  	body, err := ioutil.ReadAll(resp.Body)
  	if err != nil {
  		return nil, err
  	}
  
  	err = json.Unmarshal(body, &verifyControlResponse)
  	if err != nil {
  		return nil, err
  	}
  
  	return verifyControlResponse, nil
  }
docs: // Control the progress of Verify Requests
  // https://developer.nexmo.com/api/verify#verify-control