How does the system write a sealed sector into disk, via mmap, or directIO?

How does the system write a sealed sector into disk, via mmap, or directIO?

If I want to speed up the disk I/O, it’s better to understand more in detail. It would be helpful if anyone can direct me to the implementation of code.

The relevant code is in the rust-fil-proofs repo here. I know, probably not the most obvious place, I think we’ll rearrange it soon.

I doesn’t look like it uses mmap.