code: func (ng *Engine) cumulativeSubqueryOffset(path []Node) time.Duration {
  	var subqOffset time.Duration
  	for _, node := range path {
  		switch n := node.(type) {
  		case *SubqueryExpr:
  			subqOffset += n.Range + n.Offset
  		}
  	}
  	return subqOffset
  }
docs: // cumulativeSubqueryOffset returns the sum of range and offset of all subqueries in the path.