Function broadcast

src/thread_pool.rs:2454–2463

Runs an operation on multiple threads and returns a vector of results. When executed on a thread that is currently registered as a worker (i.e. the closure inside [`Membership::activate`], [`ThreadPool::with_worker`], or similar) this is able to look up that registration and find the worker and thread-pool implicitly. If not called within a thread pool, this uses the [`DEFAULT_POOL`]. If you ha

(f: F)

        // Wrap the operation in an `Arc` so each per-member job can own an
        // independent, `'static` reference to it. We must *not* let a job
        // capture a borrow of `f`: `spawn_broadcast` does not wait, so `f`
        // would be dropped while jobs are still queued or running on other
        // threads.
        let f = Arc::new(f);

        // Send the broadcast to each member, and wake them up.
        for (i, member_index) in members.iter_bits().enumerate() {
            let func = Arc::clone(&f);
            // Run the operation. A panic from it has nowhere to propagate,
            // and must not unwind into the executing worker, so it is caught
            // and passed to the pool's panic handler.
            let op = move |worker: &Worker| {
                let result = unwind::halt_unwinding(|| {