set thread ionice to IOPRIO_CLASS_RT on Linux

[Be-ing]

https://www.kernel.org/doc/html/latest/block/ioprio.html#scheduling-classes

Unfortunately it seems there isn't currently a way to set a thread's ionice with Rust.

[BillyDM]

So what is the issue here?

[Be-ing]

The issue is that the kernel has a feature that could be used to give creek's reader thread priority access to the storage device but this is not being taken advantage of currently.

[abique]

If you buffer enough you may not need it, but yes io nice can be interesting for disk access when you seek maybe.

[abique]

Though, setting it to RT may not necessarily be a win.