code: public OIdentifiable getKeyAt(final int iIndex) {
  		if (rids != null && rids[iIndex] != null)
  			return rids[iIndex];
  
  		final ORecordId rid = itemFromStream(iIndex);
  
  		if (rids != null)
  			rids[iIndex] = rid;
  
  		return rid;
  	}
docs: Lazy unmarshall the RID if not in memory.