code: private Iterable<Info<T, R>> find(long start, long finish, String withinHash) {
          long key = Base32.decodeBase32(withinHash);
          SortedMap<Long, Info<T, R>> sortedByTime = mapByGeoHash.get(key);
          if (sortedByTime == null)
              return Collections.emptyList();
          else
              return sortedByTime.subMap(start, finish).values();
      }
docs: Returns the {@link Info}s where start<=time <finish and position is
  inside the geohash withinHash.
  
  @param start
  start time inclusive
  @param finish
  finish time exclusive
  @param withinHash
  returned records are within hash
  @return iterable