rbacklight - xbacklight rewritten in Rust

Hey guys,
as my first Rust project I decided to rewrite xbacklight in Rust (https://github.com/procrastimax/rbacklight).
It bothered me, that you cannot really change the brightness in predefined steps in xbacklight like i.e. increase brightness by 1/20.
So I wrote rbacklight which works with XCB (like xbacklight) using the rust-xcb crate.
rbacklight also provides some additional features like formatted output, notifications (mainly for the dunst notification daemon) and multiple modes to handle values.

I would like to read some critics or suggestions!