flink-playground Requirements Java 11 Flink 1.18.1 Content Directory Window State source sink Description sumin/example/window/tumbling TumblingEventTime ValueState FromElement print Fixed window Size with 10s, allow 5s lateness sumin/example/window/sliding SlidingEventTime ValueState SourceFunction print window is sliding every 5s with 20s size, allow 5s lateness sumin/example/window/sessiom SessionEventTime ValueState KafkaSource KafkaSink window will end when time gap is 10s, allow 5s lateness