#[tokio::test(flavor = "multi_thread", worker_threads = 3)]
    async fn test_combine_latest() {
        let subject1 = Shared::behavior_subject(0_i32);
        let subject1_clone = subject1.clone();
        let subject2 = Shared::behavior_subject(0_i32);
        let mut subject2_clone = subject2.clone();

        subject1
            .combine_latest(subject2, |v1, v2| v1 + v2)
            .flat_map(move |value| {
                let subject1_clone = subject1_clone.clone();

                return Shared::from_future(async move {
                    let mut subject1_clone = subject1_clone.clone();

                    let _ = tokio::spawn(async move {
                        tokio::time::sleep(Duration::from_millis(1)).await;
                        println!("subject1 emit: {value}");
                        subject1_clone.next(value);
                    })
                    .await;

                    return value;
                });
            })
            .subscribe(|value| println!("receive: {value}"));

        Shared::from_iter(0..10000)
            .concat_map(|s| Shared::of(s).delay(Duration::from_millis(1)))
            .subscribe(move |value| {
                println!("subject2 emit: {value}");
                subject2_clone.next(value);
            });

        tokio::time::sleep(Duration::from_millis(10000)).await;
    }

subject2 emit: 4
subject1 emit: 5
receive: 5
subject1 emit: 6
subject1 emit: 5

thread 'tokio-rt-worker' (282944) panicked at .cargo/registry/src/index.crates.io-1949cf8c6b5b557f/rxrust-1.0.0-rc.5/src/subject/subject_core.rs:503:1:
re-entrant Subject emissions are not supported (next/error/complete). Use an explicit async boundary (e.g. delay(0)) if you need feedback loops.