docs: @VisibleForTesting
  	static String createIncompletePartObjectNamePrefix(String objectName) {
  		checkNotNull(objectName);
  
  		final int lastSlash = objectName.lastIndexOf('/');
  		final String parent;
  		final String child;
  
  		if (lastSlash == -1) {
  			parent = "";
  			child = objectName;
  		} else {
  			parent = objectName.substring(0, lastSlash + 1);
  			child = objectName.substring(lastSlash + 1);
  		}
  		return parent + (child.isEmpty() ? "" : '_') + child + "_tmp_";
  	}