val event = nextEvent() as Open
    return event.eventSource
  }

  fun assertClose() {
    nextEvent() as Closed
  }

  fun assertFailure(message: String?) {
    val event = nextEvent() as Failure
    if (message != null) {
      assertThat(event.t!!.message).isEqualTo(message)
    } else {
      assertThat(event.t).isNull()
    }
  }

  internal data class Open(

    assertThat(nextEvent()).isEqualTo(Ping(payload))
  }

  fun assertPong(payload: ByteString) {
    assertThat(nextEvent()).isEqualTo(Pong(payload))
  }

  fun assertClosing(
    code: Int,
    reason: String,
  ) {
    assertThat(nextEvent()).isEqualTo(Closing(code, reason))
  }

  fun assertClosed(
    code: Int,
    reason: String,
  ) {

      if (!dispatching.get()) {
        dispatching.set(true);
        try {
          Event nextEvent;
          while ((nextEvent = queueForThread.poll()) != null) {
            while (nextEvent.subscribers.hasNext()) {
              nextEvent.subscribers.next().dispatchEvent(nextEvent.event);
            }
          }
        } finally {
          dispatching.remove();
          queue.remove();

      if (!dispatching.get()) {
        dispatching.set(true);
        try {
          Event nextEvent;
          while ((nextEvent = queueForThread.poll()) != null) {
            while (nextEvent.subscribers.hasNext()) {
              nextEvent.subscribers.next().dispatchEvent(nextEvent.event);
            }
          }
        } finally {
          dispatching.remove();
          queue.remove();

		}
		r.spillErr = err

		// Reset CPU samples cursor.
		r.cpuSamples = r.gen.cpuSamples

		// Reset frontier.
		for m, batches := range r.gen.batches {
			bc := &batchCursor{m: m}
			ok, err := bc.nextEvent(batches, r.gen.freq)
			if err != nil {
				return Event{}, err
			}
			if !ok {
				// Turns out there aren't actually any events in these batches.
				continue
			}

type batchCursor struct {
	m       ThreadID
	lastTs  Time
	idx     int       // next index into []batch
	dataOff int       // next index into batch.data
	ev      baseEvent // last read event
}

func (b *batchCursor) nextEvent(batches []batch, freq frequency) (ok bool, err error) {
	// Batches should generally always have at least one event,
	// but let's be defensive about that and accept empty batches.

	}
	if x == "" {
		return +1
	}
	if y == "" {
		return -1
	}
	for x != "" && y != "" {
		x = x[1:] // skip - or .
		y = y[1:] // skip - or .
		var dx, dy string
		dx, x = nextIdent(x)
		dy, y = nextIdent(y)
		if dx != dy {
			ix := isNum(dx)
			iy := isNum(dy)
			if ix != iy {
				if ix {
					return -1
				} else {
					return +1
				}
			}
			if ix {