inconsistency in native class extension duration

I am working on perfs and spending a lot of time on profiling timelines.
I see very weird inconsistencies in materializing and native class `extending.

This is 2 different app starts with the same exact code. Globally everything is the same except for those "yellow" times.
Here it is a factor 10 which is pretty big.

I add this mostly to start the discussion on what could be the reason for that and how we can make sure we get the smallest one.

• could that be do to profiling?
• @darind do you have an opinion on this?
• here it is in debug, but i see the same kind in production. The difference might be smaller though i am not sure. Can debug/production make a difference for this?

No source files, tests, or entry points are named. Start by reproducing two app starts with identical code in debug and production while comparing profiling timelines, and investigate whether profiling or build mode accounts for the materializing and native class extension variance. Done should document the cause and an agreed way to measure or minimize it.