Minor annoyance - display unused rest time

Is there any way to display the amount of rest time that didn't get
used because of disturb?

For example, I rest 100 turns so I avoid the "Looks like any other
level" message because the closest down stairs are 5 spaces away from
where I entered the level.  While I'm resting, a single orc shaman
comes into LoS.  Now I don't know how long I've rested because I'm
still full and I've got permanent light.

So I rest 100 again, and this time I get notified that I feel the
gauntlets I'm carrying are cursed and I drop them.  Again, used less
than the 100 turns AFAICT.

Rest 100 again, and a green centipede comes in.  Repeat ad nauseum
until nothing disturbs, because each time I might have rested only 5
turns.

Only a minor annoyance.