DataStream 转化为 AllWindowedStream
DataStream.timeWindowAll(...) -> AllWindowedStream
DataStream.countWindowAll(...) -> AllWindowedStream
DataStream.windowAll(...) -> AllWindowedStream

DataStream 转化为 KeyedStream
DataStream.keyBy(...) -> KeyedStream

KeyedStream 转化为 WindowedStream
KeyedStream.timeWindow(...) -> WindowedStream
KeyedStream.countWindow(...) -> WindowedStream
KeyedStream.window(...) -> WindowedStream