code: func (pool *TxPool) Stop() {
  	// Unsubscribe all subscriptions registered from txpool
  	pool.scope.Close()
  
  	// Unsubscribe subscriptions registered from blockchain
  	pool.chainHeadSub.Unsubscribe()
  	pool.wg.Wait()
  
  	if pool.journal != nil {
  		pool.journal.close()
  	}
  	log.Info("Transaction pool stopped")
  }
docs: // Stop terminates the transaction pool.