nodejs socket.io can not emit internal event

I am trying to emit logout event to erase client session and disconnect him. But I can not find proper solution online to do it. here is my code with comments:

exports.post = function(req, resp, next) {
    var sid = req.session.id;

    var io = req.app.settings.io;//import io object with event listeners

    req.session.destroy(function(err) {
        io.sockets.$emit('session:reload');//here I am trying to emit internal event but it does not work - says that it is not a function
        if(err) return next(err);
        resp.redirect('/');
    });
}

Please help. In documentation there is nothing about this part.

via ovod