code: func (k *KV) Keys(prefix, separator string, q *QueryOptions) ([]string, *QueryMeta, error) {
  	params := map[string]string{"keys": ""}
  	if separator != "" {
  		params["separator"] = separator
  	}
  	resp, qm, err := k.getInternal(prefix, params, q)
  	if err != nil {
  		return nil, nil, err
  	}
  	if resp == nil {
  		return nil, qm, nil
  	}
  	defer resp.Body.Close()
  
  	var entries []string
  	if err := decodeBody(resp, &entries); err != nil {
  		return nil, nil, err
  	}
  	return entries, qm, nil
  }
docs: // Keys is used to list all the keys under a prefix. Optionally,
  // a separator can be used to limit the responses.