/**
  * @param \Magento\Checkout\Model\ShippingInformationManagement $subject
  * @param $cartId
  * @param \Magento\Checkout\Api\Data\ShippingInformationInterface $addressInformation
  */
 public function beforeSaveAddressInformation(\Magento\Checkout\Model\ShippingInformationManagement $subject, $cartId, \Magento\Checkout\Api\Data\ShippingInformationInterface $addressInformation)
 {
     $customFee = $addressInformation->getExtensionAttributes()->getFee();
     $quote = $this->quoteRepository->getActive($cartId);
     if ($customFee) {
         $fee = $this->dataHelper->getCustomFee();
         $quote->setFee($fee);
     } else {
         $quote->setFee(NULL);
     }
 }