code: @Override
      public ModifyEventSubscriptionResult modifyEventSubscription(ModifyEventSubscriptionRequest request) {
          request = beforeClientExecution(request);
          return executeModifyEventSubscription(request);
      }
docs: <p>
  Modifies an existing AWS DMS event notification subscription.
  </p>
  
  @param modifyEventSubscriptionRequest
  @return Result of the ModifyEventSubscription operation returned by the service.
  @throws ResourceQuotaExceededException
  The quota for this resource quota has been exceeded.
  @throws ResourceNotFoundException
  The resource could not be found.
  @throws SNSInvalidTopicException
  The SNS topic is invalid.
  @throws SNSNoAuthorizationException
  You are not authorized for the SNS subscription.
  @throws KMSAccessDeniedException
  The ciphertext references a key that doesn't exist or DMS account doesn't have an access to
  @throws KMSDisabledException
  The specified master key (CMK) isn't enabled.
  @throws KMSInvalidStateException
  The state of the specified KMS resource isn't valid for this request.
  @throws KMSNotFoundException
  The specified KMS entity or resource can't be found.
  @throws KMSThrottlingException
  This request triggered KMS request throttling.
  @sample AWSDatabaseMigrationService.ModifyEventSubscription
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/dms-2016-01-01/ModifyEventSubscription" target="_top">AWS
  API Documentation</a>