code: @SuppressWarnings("unused") // called through reflection by RequestServer
    public TimelineV3 fetch(int version, TimelineV3 s) {
      Timeline t = s.createAndFillImpl();
      t.snapshot = new TimelineSnapshot(H2O.CLOUD,TimeLine.system_snapshot());
      return s.fillFromImpl(t);
    }
docs: TODO: should return a base class for TimelineVx