How to send HTTP PUT request from Haxe/Neko?

I have a server running under NekoVM which provide a RESTLike service. I am trying to send a PUT/DELETE request to this server using the following Haxe code :

static public function main()
{
    var req : Http = new Http("http://localhost:2000/add/2/3");
    var bytesOutput = new haxe.io.BytesOutput();

    req.onData = function (data)
    {
        trace(data);
        trace("onData");
    }

    req.onError = function (err)
    {
        trace(err);
        trace("onError");
    }

    req.onStatus = function(status)
    {
        trace(status);
        trace("onStatus");
        trace (bytesOutput);
    }

    //req.request(true); // For GET and POST method

    req.customRequest( true, bytesOutput , "PUT" );

}

The problem is that only the onStatus event is showing something :

Main.hx:32: 200
Main.hx:33: onStatus
Main.hx:34: { b => { b => #abstract } }

Can anyone explain me what I am doing wrong with customRequest ?

customRequest does not call onData.

After customRequest call is finished either onError was called or first onStatus was called, then response was written to specified output.