tech debt: async version of pread

[sehz]

We use low-level pread to perform block read, a synchronous operation. We need to build an async version. Here is scope:

1. Centralize pread operation. This should be a fallback if async I/O is not available. We have duplicate usage. Preferably use https://github.com/bytecodealliance/rustix if possible instead of nix or libc.
2. IO-Uring backend for Linux.
3. Async I/O for Darwin (Mac). I believe there is I/O file API on BSD. This is a low priority. Can move to separate issue if first two objects are accomplished.

The API can be moved to https://github.com/infinyon/future-aio

[sehz]

related to this: #2215

[matheus-consoli]

Hi, I want to take a look into this 🙂

[EstebanBorai]

Hi, I want to take a look into this 🙂

Of course! Feel free to ask any questions here!

[EstebanBorai]

@matheus-consoli not sure if you are in our Discord already, but just un case: https://discord.gg/3nBFxRZy.

There you can have access to a quicker prompt!

[sehz]

Another usage of pread #3519