Function use_side_effect 

pub fn use_side_effect(callback: impl FnMut() + 'static)

Registers a callback that will run every time a State which was .read() inside, changes.

let state = use_state(|| 0);

use_side_effect(move || {
    // The moment `.read()` is called this side effect callback gets subscribed to it
    let value = *state.read();
    println!("{value}");
});