code: public <T> Future<?> loadData(Iterator<Map.Entry<String, T>> i) {
      Future<Boolean> mostRecent = null;
      while (i.hasNext()) {
        Map.Entry<String, T> e = i.next();
        mostRecent = push(e.getKey(), e.getValue());
        watch(e.getKey(), mostRecent);
      }
  
      return mostRecent == null ? new ImmediateFuture(true) : mostRecent;
    }
docs: Load data from the given iterator.
  
  @param <T> type of data being loaded
  @param i the iterator of data to load