docs: protected void reportAllElementKeyGroups() {
  
  		Preconditions.checkState(partitioningSource.length >= numberOfElements);
  
  		for (int i = 0; i < numberOfElements; ++i) {
  			int keyGroup = KeyGroupRangeAssignment.assignToKeyGroup(
  				keyExtractorFunction.extractKeyFromElement(partitioningSource[i]), totalKeyGroups);
  			reportKeyGroupOfElementAtIndex(i, keyGroup);
  		}
  	}