Change tray icon or something like badge text for icon

[Zoe]

Seems currently tray icon cannot be changed on the fly after the first time installed.

As I'm developing a notification app and I want to show notification number on the icon, so I want to change the icon dynamically.

Chrome extension can have badge text on the icon, it's like a attribute of the icon, like attached screenshot: 

Node webkit supports alternative icon on mac? And not in win right?

I tried tray.icon="change.png" on the fly, no luck on this.

So, badge text or change icon are both not supported in win?

Regards