Close the readable stream

The problem is that I can not find how to stop flushing the file data. I tried the unpipe() method. And it seems working when requesting the file from the curl and then closing it. But it does not stops flushing the file when closing the browser. And entire file is read. How can I stop it?

var http = require("http"),
fs = require("fs"),
url = require("url");

var stream;

var requestHandlers = {

    video: function(request, response) {
        var totalbytes = 0;
        response.writeHead(200, {"Content-Type": "video/mp4"});

        stream = fs.createReadStream('video.mp4');
        stream.pipe(response);
        stream.on('data', function(chunk) {
            totalbytes += chunk.length;
        });

        stream.on('end', function(){
            console.log("Video connection ended. Total bytes sent %d", totalbytes);
        });

        stream.on('close', function(){
            console.log("Video connection closed. Total bytes sent %d", totalbytes);
        });

    }
}

var handle = {
    "/video.mp4": requestHandlers.video
};

var myServer = http.createServer(function (request, response) {

    var pathname = url.parse(request.url).pathname;
    console.log("Request for " + pathname + " received from " + request.connection.remoteAddress);

    if (typeof handle[pathname] === 'function') {
        handle[pathname](request, response);
    } else {
        response.writeHead(404, {"Content-Type": "text/html"});
        response.write("404 Not found");
        response.end();
    }

    request.on('close', function(){
//      stream.unpipe();    //does not help
        console.log("Connection closed");
    });
});

myServer.listen(5555);
console.log("Server started");