code: @Override
      public CancelExportTaskResult cancelExportTask(CancelExportTaskRequest request) {
          request = beforeClientExecution(request);
          return executeCancelExportTask(request);
      }
docs: <p>
  Cancels an active export task. The request removes all artifacts of the export, including any partially-created
  Amazon S3 objects. If the export task is complete or is in the process of transferring the final disk image, the
  command fails and returns an error.
  </p>
  
  @param cancelExportTaskRequest
  Contains the parameters for CancelExportTask.
  @return Result of the CancelExportTask operation returned by the service.
  @sample AmazonEC2.CancelExportTask
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/ec2-2016-11-15/CancelExportTask" target="_top">AWS API
  Documentation</a>