Updates badge text and style of the toolbar item with 
id.
    setCount(id, count, [className], [style])
    
    
        | id | string, id of the toolbar item | 
    
        | count | text, count for the toolbar item, can be plain text | 
    
        | className | text, (optional) custom class for the badge | 
    
        | style | text, (optional) additional style for the badge | 
    
 
Returns undefined.
Description
The first argument 
id is the id of the toolbar item you used when you created toolbar items. The
.items array holds all created toolbar items.
If you have toolbar defined in the following way:
You can update badge by