Notification message and dismiss request

Hello!

I was wondering if it's possible to add a **custom message** feature for the notification, that we can set on the 'enqueue' method, so that the notification shows that message instead of the filename; something like "Downloading images for Musée d'Orsay".
Also, it would be nice to have a method or something to **automatically dismiss the notification** for a given task id (e.g. when the download is finished).