code: func newQuery(collection *Collection) *query {
  	q := &query{
  		collection: collection,
  		pool:       collection.pool,
  	}
  	// For now, only indexed collections are queryable. This might change in
  	// future versions.
  	if !collection.index {
  		q.setError(fmt.Errorf("zoom: error in NewQuery: Only indexed collections are queryable"))
  		return q
  	}
  	return q
  }
docs: // newQuery creates and returns a new query with the given collection. It will
  // add an error to the query if the collection is not indexed.