Corrupting websocket test code

socket.go

const testSize = 200
const maxPacketSize = 4096

var upgrader = websocket.Upgrader{
	ReadBufferSize:  maxPacketSize,
	WriteBufferSize: maxPacketSize,
	CheckOrigin: func(r *http.Request) bool {
		return true
	},
}

func wsHandler(w http.ResponseWriter, req *http.Request) {
	packets := 0
	conn, err := upgrader.Upgrade(w, req, nil)
	if err != nil {
		log.Fatal(err)
	}
	for {
		rcv := make([]byte, testSize)
		_, r, err := conn.NextReader()
		if err != nil {
			log.Println(err)
			continue
		}
		_, err = r.Read(rcv)
		if err != nil {
			log.Fatal(err)
		}
		for i := range rcv {
			if rcv[i] != byte(i % 255) {
				log.Fatalf("Packet %d: %d != %d (%v)", packets, rcv[i], i, rcv)
			}
			packets++
		}
	}
}

func main() {
	var data [testSize]byte
	for i := range data {
		data[i] = byte(i % 255)
	}

	if len(os.Args) >= 2 && os.Args[1] == "serve" {
		http.HandleFunc("/ws", wsHandler)
		log.Println(http.ListenAndServe("127.0.0.1:8080", nil))
	} else {
		conn, _, err := websocket.DefaultDialer.Dial("ws://127.0.0.1:8080/ws", nil)
		if err != nil {
			log.Fatal(err)
		}
		for {
			if err := conn.WriteMessage(websocket.BinaryMessage, data[:]); err != nil {
				log.Fatal(err)
			}
		}
	}
}