void BCSP_IoDecrement() {
    int pending;
    pending = __VERIFIER_atomic_dec();
    if (pending == 0) {
        stoppingEvent = 1;
    }
}
inline void my_thread2()
{
  __VERIFIER_atomic_acquire(&mutexb);
  __VERIFIER_atomic_dec();
  __VERIFIER_atomic_inc();
  __VERIFIER_atomic_release(&mutexb);
}