notmuch.el: "wash" date in message display

[Matt Armstrong]

I miss some of the Gnus "wash" functions available for message display.
There was one that either reformatted the Date: header into my time
zone, or displayed the Date in terms of elapsed time from now (e.g. 1
hour ago, 1 day ago, etc.).  I don't remember which, but I'd be happy
with either.

Has anybody integrated a feature like that into notmuch.el?  It wouldn't
be hard, but I'd feel dumb if I did the work and there was some variable
I could set to get a similar effect.