Controller/Order/Save.php
private function clearQuoteSession($quote)
    {
        $this->checkoutSession->setLastQuoteId($quote->getId())
                              ->setLastSuccessQuoteId($quote->getId())
                              ->clearHelperData();
    }
private function clearQuoteSession($quote)
    {
        $this->checkoutSession->setLastQuoteId($quote->getId())
                              ->setLastSuccessQuoteId($quote->getId())
                              ->clearHelperData();
    }
private function clearQuoteSession ( $ quote ) { $ this -> checkoutSession -> setLastQuoteId ( $ quote -> getId ( ) ) -> setLastSuccessQuoteId ( $ quote -> getId ( ) ) -> clearHelperData ( ) ; }
Clear quote session after successful order

@param Quote $quote

@return void
Clear quote session after successful order