如何对WindowedStream数据使用公制或类似的东西？

import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.windowing.time.Time;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.api.common.functions.MapFunction;

public class WindowedStreamExample {
    public static void main(String[] args) throws Exception {
        final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        DataStream<Integer> dataStream = env.fromElements(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);

        DataStream<Integer> windowedStream = dataStream
            .map(new MapFunction<Integer, Integer>() {
                @Override
                public Integer map(Integer value) {
                    return value;
                }
            })
            .keyBy(value -> 0) // 使用一个固定的键
            .timeWindow(Time.seconds(5)) // 定义一个5秒的时间窗口
            .sum(0); // 对窗口内的元素求和

        windowedStream.print();

        env.execute("WindowedStream Example");
    }
}