As a member of that group, Hacker News is not where I come for answers to my questions. I think it's perfectly reasonable for comments here to assume that the readers of the comment aren't in that group. Either you know what you're doing enough that 99.9% of the internet is not helpful to you, or you're probably up shit creek without a paddle anyway until you figure out enough to move into the first group.

Then they'll use ASM, manual SIMD or pointers arithmetic like they would do in C and that would work. All of theses are part of the unsafe Rust (inline ASM is nightly only though, but you can still link to a ASM file even in stable).