Make use of offset argument to improve performance

[wasamasa]

This builds upon #2 which did most of the work. For some reason the original PR did hardcode the offset to 0 and instead created copies of the array with an increasing offset instead.

Before: Initiating a X connection with xcb:connect took between 2.4 and 2.9s

After: Initiating a X connection with xcb:connect now takes 0.31 to 0.33s

[lechner]

Hi,

I deployed EXWM built on this branch via my custom channel in Guix. EXWM works fine and seems to start a few seconds faster.

Thank you for maintaining this great little library!

Kind regards Felix Lechner

[lechner]

Hi,

This PR has another positive side effect. Aside from the speed up, it fixed an annoying problem I've had with my multi-head setup for a while.

Previously, my third monitor would only come up about sixty percent of the time, although I'm not sure how to explain that interaction with xrandr in my init.el. That's now fixed!

Kind regards Felix

[minad]

@Stebalien Have you seen this patch? What do you think about it?

[Stebalien]

This seems completely reasonable. (and @wasamasa has his papers in order, unless I'm mistaken).

[Stebalien]

But the fact that emacs-exwm/xelb isn't a fork is really annoying when it comes to porting PRs...