There is almost never a step three.
But if there is, it's this: Step three: measure.
Now enter a loop of "try something, measure, go to step 2".
Of the things you can try, optimizing GC overhead is but one of many options. Arenas are but one of many options for how to do that.
And the thing about performance optimizations are that they can be intensely local. If you can remove 100% of the allocations on just the happy path inside of one hot loop in your code, then when you loop back to step two, you might find you are done. That does not require an arena allocator with global applicability.
Go gives realistic programmers the right tools to succeed.
And Go's limitations give people like the author plenty of ammunition to fight straw men that don't exist. Tant pis.
Work out a zero knowledge way to verify age, and implement it. It won't be easy, but it also won't require breaking the rules of mathematics as per most of the governmental requests to 'safely' backdoor encryption.
The Swiss citizens just approved a system like this.
Deleted Comment
Deleted Comment