You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: compare_read_only.rs
    path of file: ./repos/optimistic_lock_coupling_rs/benches/benchmarks
    
    the code of the file until where you have to start completion: use criterion::{criterion_group, BenchmarkId, Criterion, Fun, ParameterizedBenchmark};

use super::ListMutex;
use super::ListOLock;

fn read_only_list_mutex(i: i32) {
    static mut lock: Option<ListMutex> = None;
    unsafe { lock = Some(ListMutex
    
fn lock_read_only_list(c: &mut Criterion) {
    let mx = Fun::new("Mutex", |b, i| b.iter(|| read_only_list_mutex(*i)));
    let ol = Fun::new("OptimisticLockCoupling", |b, i| {
        b.iter(|| read_only_list_optimistic_lock_coupling(*i))
    });

    let functions = vec![ol, mx];

    c.bench_functions("Lock Read Only List Compare", functions, 1_000_000);
}