Code shared from the Rust Playground

playground.rs

pub fn func_a<T: AsRef<[u8]>>(input: T) -> Vec<u8> {
   unimplemented!()
}

pub fn func_b<F>(func: F)
where
    F: Fn(&[u8]) -> Vec<u8>,
{
    let input: Vec<u8> = vec![0, 1, 2, 3];
    let output = func(input.as_ref());
    unimplemented!()
}

fn main() {
    func_b(func_a)
}