Feature request - Queable messages

I looked around for a bit and couldn't find any similar feature requests, so here it is.

I've often wanted to send my friends a message, but didn't want to bother them at the time. But when I told myself I'd send it later, I would often completely forget about it. It would be nice if there was a 'send later' or 'send at date/time' functionality for these kinds of situations.