code: func (e *IndexReaderExecutor) Close() error {
  	err := e.result.Close()
  	e.result = nil
  	if e.runtimeStats != nil {
  		copStats := e.ctx.GetSessionVars().StmtCtx.RuntimeStatsColl.GetRootStats(e.plans[0].ExplainID().String())
  		copStats.SetRowNum(e.feedback.Actual())
  	}
  	e.ctx.StoreQueryFeedback(e.feedback)
  	return err
  }
docs: // Close clears all resources hold by current object.