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: timer.rs
    path of file: ./repos/pingora/pingora-timeout/src
    
    the code of the file until where you have to start completion: // Copyright 2024 Cloudflare, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
    
    async fn test_timer_manager_pause() {
        let tm_a = Arc::new(TimerManager::new());
        let tm = tm_a.clone();
        std::thread::spawn(move || tm_a.clock_thread());

        let now = Instant::now();
        let t1 = tm.register_timer(Duration::from_secs(2));
        tm.pause_for_fork();
        // no actual fork happen, we just test that pause and unpause work

        // any timer in this critical section is timed out right away
        let t2 = tm.register_timer(Duration::from_secs(2));
        t2.poll().await;
        assert_eq!(now.elapsed().as_secs(), 0);

        std::thread::sleep(Duration::from_secs(1));
        tm.unpause();
        t1.poll().await;
        assert_eq!(now.elapsed().as_secs(), 2);
    }