@Override
public void flatMap(WindowedValue<IN> value, Collector<WindowedValue<OUTFL>> out)
throws Exception {
this.initContext(doFn, out);
// for each window the element belongs to, create a new copy here.
Collection<? extends BoundedWindow> windows = value.getWindows();
if (windows.size() <= 1) {
processElement(value);
} else {
for (BoundedWindow window : windows) {
processElement(
WindowedValue.of(value.getValue(), value.getTimestamp(), window, value.getPane()));
}
}
}
