in sample-apps/spark/src/main/java/com/amazon/sampleapp/App.java [135:140]
private static int mimicQueueSizeChange() {
int newQueueSize = ThreadLocalRandom.current().nextInt(100);
int queueSizeChange = newQueueSize - mimicQueueSize;
mimicQueueSize = newQueueSize;
return queueSizeChange;
}