code: public ObjectMetadata getObject(GetObjectRequest request, File destinationFile) {
          checkNotNull(request, "request should not be null.");
          checkNotNull(destinationFile, "destinationFile should not be null.");
  
          BosObject bosObject = this.getObject(request);
          this.downloadObjectToFile(bosObject, destinationFile, request.getRange() == null);
          return bosObject.getObjectMetadata();
      }
docs: Gets the object metadata for the object stored in Bos under the specified bucket and key,
  and saves the object contents to the specified file.
  Returns <code>null</code> if the specified constraints weren't met.
  
  @param request The request object containing all the options on how to download the Bos object content.
  @param destinationFile Indicates the file (which might already exist) where to save the object
  content being downloading from Bos.
  @return All Bos object metadata for the specified object.
  Returns <code>null</code> if constraints were specified but not met.