Add a note for differences in the release and debug mode.

[alarshi]

@gassmoeller and I noticed that the difference in speeds in the main GWB and our local branch of GWB for our Global models is only in the debug mode and not in the release mode (#536), with a majority of time spent in the output stream operator. This is not an issue to fix, but maybe it would be useful to document this somewhere. This PR addresses this.

[gassmoeller]

Thanks, looks good!

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (b72ce04) 93.49% compared to head (37aa34c) 93.49%.
Report is 6 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #553   +/-   ##
=======================================
  Coverage   93.49%   93.49%           
=======================================
  Files          92       92           
  Lines        6346     6346           
=======================================
  Hits         5933     5933           
  Misses        413      413           

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[github-actions]

Benchmark	Main	Feature	Difference (99.9% CI)
Slab interpolation simple none	1.023 ± 0.003 (s=402)	1.023 ± 0.004 (s=480)	-0.0% .. +0.1%
Slab interpolation curved simple none	1.027 ± 0.003 (s=441)	1.031 ± 0.008 (s=436)	+0.2% .. +0.5%
Spherical slab interpolation simple none	1.261 ± 0.005 (s=349)	1.261 ± 0.006 (s=367)	-0.1% .. +0.1%
Slab interpolation simple curved CMS	1.099 ± 0.005 (s=430)	1.100 ± 0.003 (s=391)	-0.1% .. +0.1%
Spherical slab interpolation simple CMS	1.859 ± 0.010 (s=239)	1.860 ± 0.010 (s=247)	-0.1% .. +0.2%
Spherical fault interpolation simple none	1.273 ± 0.012 (s=357)	1.272 ± 0.005 (s=353)	-0.3% .. +0.1%
Cartesian min max surface	2.360 ± 0.016 (s=201)	2.364 ± 0.019 (s=183)	-0.1% .. +0.4%
Spherical min max surface	7.355 ± 0.027 (s=62)	7.351 ± 0.020 (s=63)	-0.2% .. +0.1%