code: public Map<K,WindowFuture<K,R,P>> createSortedSnapshot() {
          Map<K,WindowFuture<K,R,P>> sortedRequests = new TreeMap<K,WindowFuture<K,R,P>>();
          sortedRequests.putAll(this.futures);
          return sortedRequests;
      }
docs: Creates an ordered snapshot of the requests in this window.  The entries
  will be sorted by the natural ascending order of the key.  A new map
  is allocated when calling this method, so be careful about calling it
  once.
  @return A new map instance representing all requests sorted by
  the natural ascending order of its key.