Function timed_lock 

pub fn timed_lock<'a, T>(mutex: &'a Mutex<T>, ctx: &str) -> MutexGuard<'a, T>
where
    T: ?Sized,

Acquire a mutex guard with timing and poison recovery.

Logs a warning if acquisition takes > 5 ms (contention hot-spot indicator). Recovers from a poisoned mutex rather than propagating the error.