code: public static boolean isDownloadParallelizable(final AmazonS3 s3, final GetObjectRequest getObjectRequest,
              Integer partCount) {
          ValidationUtils.assertNotNull(s3, "S3 client");
          ValidationUtils.assertNotNull(getObjectRequest, "GetObjectRequest");
  
          if (s3 instanceof AmazonS3Encryption || getObjectRequest.getRange() != null
                  || getObjectRequest.getPartNumber() != null || partCount == null) {
              return false;
          }
          return true;
      }
docs: Returns true if the specified download request can use parallel part
  downloads for increased performance.
  
  @param getObjectRequest
  The request to check.
  
  @param s3
  The Amazon s3 client.
  
  @return True if this request can use parallel part downloads.