public void addTimeline(TimelineEvent event) {
    timeline.add(event);
  }
@Test
  public void testAddDuplicateTimelineEvents() {
    WorkflowRuntimeSummary summary = new WorkflowRuntimeSummary();
    TimelineEvent event = TimelineLogEvent.info("hello world");
    summary.addTimeline(event);
    summary.addTimeline(TimelineLogEvent.info("hello world"));
    summary.addTimeline(TimelineLogEvent.info("hello world"));
    summary.addTimeline(TimelineLogEvent.info("hello world"));
    assertEquals(Collections.singletonList(event), summary.getTimeline().getTimelineEvents());
  }