clientListener.assertOpen()
    val server = serverListener.assertOpen() as RealWebSocket
    val startNanos = System.nanoTime()
    while (webSocket.receivedPongCount() < 3) {
      Thread.sleep(50)
    }
    val elapsedUntilPong3 = System.nanoTime() - startNanos
    assertThat(TimeUnit.NANOSECONDS.toMillis(elapsedUntilPong3).toDouble())
      .isCloseTo(1500.0, 250.0)