Is Ordering::Relaxed strong enough?

[fzyzcjy]

Hi, I wonder whether Relaxed is strong enough or not? https://doc.rust-lang.org/std/sync/atomic/enum.Ordering.html says:

No ordering constraints, only atomic operations.

Thus, it may look reasonable to allow users to configure it. For example, a user who wants the counter to be visible to all threads may need a stronger guarantee.

[JackThomson2]

I used relaxed as the sum is never going to be exact due to the sharding. Making it configurable sounds a good idea though, I'll add that in!