据我所知，窗口聚合的更改日志主题应该为每个窗口至少包含一个键/值？

input
  .groupByKey() // group by user
  .windowedBy(
    TimeWindows
      .of(Duration.ofSeconds(60))
      .advanceBy(Duration.ofSeconds(10))
      .grace(Duration.ofSeconds(60)))
  .aggregate(
    () -> new Aggregate(config),
    (userId, msg, aggregate) -> aggregate.addAndReturn(msg),
    Materialized
      .<String, Aggregate>as(inMemoryWindowStore(
        config.getOutputStore(),
        Duration.ofSeconds(300),
        Duration.ofSeconds(60),
        false))
      .withCachingDisabled()
      .withKeySerde(Serdes.String())
      .withValueSerde(new MyCustomSerde()));

当我查询状态存储时，我希望为每个窗口获得一个键/值：

WindowStoreIterator<Aggregate> iter = store.fetch(userId, start, end)

但是要么我什么也得不到（迭代器是空的），要么有时它小于开始到结束之间的实际窗口数。