}

  private fun drainCancelQueue(eventSource: EventSource) {
    if (cancel) {
      cancel = false
      eventSource.cancel()
    }
  }

  private fun nextEvent(): Any {
    return events.poll(10, TimeUnit.SECONDS)
      ?: throw AssertionError("Timed out waiting for event.")
  }

  fun assertExhausted() {
    assertThat(events).isEmpty()
  }

  fun assertEvent(
    id: String?,