clientListener.assertOpen()
    val server = serverListener.assertOpen()

    // Server to client message big enough to be compressed.
    val message1 = repeat('a', RealWebSocket.DEFAULT_MINIMUM_DEFLATE_SIZE.toInt())
    server.send(message1)
    clientListener.assertTextMessage(message1)

    // Client to server message big enough to be compressed.
    val message2 = repeat('b', RealWebSocket.DEFAULT_MINIMUM_DEFLATE_SIZE.toInt())