public int size() {
        return events.size();
    }
@Test
    public void testSize() {
        assertEquals(1, batchEventData.size());
        assertEquals(1, batchEventDataSameAttribute.size());
        assertEquals(1, batchEventDataOtherSource.size());
        assertEquals(1, batchEventDataOtherPartitionId.size());
        assertEquals(1, batchEventDataOtherEvent.size());
        assertEquals(0, batchEventDataNoEvent.size());
    }