public void test_measurepoint_save(){
    Kryo kryo = SerializeUtil.createKryo();
    Output output = new Output(66666);
    
    kryo.writeClassAndObject(output, new MeasurePointData("1111"));
    int oldPos = output.position();
    kryo.writeClassAndObject(output, new MeasurePointData("1111"));
    assertEquals(oldPos+19,output.position());//only key is written not string again
    kryo.writeClassAndObject(output, new MeasurePointData("1111"));
    kryo.writeClassAndObject(output, new MeasurePointData("2222"));
    kryo.writeClassAndObject(output, new MeasurePointData("2222"));