使用“std::sync::Barrier”时如何选择线程引线?

来自 implementation 属于 wait() :

pub fn wait(&self) -> BarrierWaitResult {
    let mut lock = self.lock.lock().unwrap();
    let local_gen = lock.generation_id;
    lock.count += 1;
    if lock.count < self.num_threads {
        let _guard =
            self.cvar.wait_while(lock, |state| local_gen == state.generation_id).unwrap();
        BarrierWaitResult(false)
    } else {
        lock.count = 0;
        lock.generation_id = lock.generation_id.wrapping_add(1);
        self.cvar.notify_all();
        BarrierWaitResult(true)
    }
}

它似乎保留了所有线程的计数。当一个给定的线程聚合时,如果它是最后一个线程,它将成为前导线程( BarrierWaitResult(true) ),否则它将成为非领导者( BarrierWaitResult(false) ).