@Override
        public ValueAndTimestamp<VAgg> get(final Windowed<KIn> windowedKey) {
            final KIn key = windowedKey.key();
            return windowStore.fetch(key, windowedKey.window().start());
        }
Created to handle records where 0 < inputRecordTimestamp < timeDifferenceMs. These records would create
windows with negative start times, which is not supported. Instead, we will put them into the [0, timeDifferenceMs]
window as a "workaround", and we will update or create their right windows as new records come in later
streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamSlidingWindowAggregate.java