client.send(message4)
    serverListener.assertTextMessage(message4)

    // Server to client message that shares context with message1.
    val message5 = message1 + message1
    server.send(message5)
    clientListener.assertTextMessage(message5)

    // Client to server message that shares context with message2.
    val message6 = message2 + message2
    client.send(message6)