@Override
 public List<PersistentChosenBlock> makeBlocks(
     PersistentChosenRequest request,
     RequestScheduler sched,
     ObjectContainer container,
     ClientContext context) {
   if (persistent) container.activate(segment, 1);
   // FIXME why is the fetching keys list not passed in? We could at least check for other fetchers
   // for the same key??? Need to modify the parameters ...
   List<PersistentChosenBlock> blocks = segment.makeBlocks(request, sched, container, context);
   if (persistent) container.deactivate(segment, 1);
   return blocks;
 }