in long-ride-alerts/src/solution/java/org/apache/flink/training/solutions/longrides/LongRidesSolution.java [151:159]
public void onTimer(long timestamp, OnTimerContext context, Collector<Long> out)
throws Exception {
// the timer only fires if the ride was too long
out.collect(rideState.value().rideId);
// clearing now prevents duplicate alerts, but will leak state if the END arrives
rideState.clear();
}