compare binary search with eytzinger

search_comparison.rs

let now = Instant::now();
for (index, e) in vec_clone.iter().enumerate() {
    assert_eq!(first_index_for_eytzinger(&vec_clone, e).expect(""), index)
}
let eytz_search = now.elapsed();

let now = Instant::now();
for (index, e) in vec_unstable.iter().enumerate() {
    assert_eq!(vec_unstable.binary_search(e).expect(""), index)
}
let binary_search = now.elapsed();