UX - optimistic 'mark read' state

[roadscape]

Is there a way to reduce the time it takes for the "Mark as read" to complete? I find it quite slow atm

Condenser should continue to fetch latest state in the background, but do not show the spinner while waiting.

Side note: we need to double-check that the "markread" operation uses the timestamp of the newest notification, as opposed to the system time. Otherwise, any new notifications (between the time of loading the page and clicking "mark read") will erroneously be marked as read.