I have a keyword-triggered workflow which does its work in the background, and I want to display a notification when the task is done for some short duration. Currently, I did that by outputs>post notification. However, with this method, although the alert automatically goes away, the history notification remains in the notification center. What I want is a notification that appears for a while and then completely disappears. How to clear it from the notification center or is there an alternative way to achieve this temporary notice?