Replace std::sync::<Lock> with parking_lot lib about madsim

[wangrunji0408]

I have done this in #41 (replacing std lock with spin).
In fact, since everything is running on a single thread, we know that there won't be any contention but it's possible to be deadlock. So what we really want is something like RefCell but also Sync. It should panic once try_lock failed.

[rogercloud]

I have done this in #41 (replacing std lock with spin). In fact, since everything is running on a single thread, we know that there won't be any contention but it's possible to be deadlock. So what we really want is something like RefCell but also Sync. It should panic once try_lock failed.

We can't guarantee the single thread scenario as a multi-thread runtime, such as tokio, may be adopted. I guess you mean single thread in sim scenario.

[wangrunji0408]

Oh yes. I'll do it for std part soon.