messageCount++
      val queueSize = webSocket.queueSize()
      assertThat(queueSize).isBetween(0L, messageCount * message.size)
      // Expect to fail before enqueueing 32 MiB.
      assertThat(messageCount).isLessThan(32L)
    }

    // Confirm all sent messages were received, followed by a client-initiated close.
    val server = serverListener.assertOpen()
    for (i in 0 until messageCount) {