Async Pest

[ekechinwokah]

Hi - made some changes to use pest in async, largely borrowed from this code discussed in a previous issue.

Is there any interest in merging into the master branch? Either way is fine but wanted to check.

[NoahTheDuke]

It looks like the only changes is from alloc::rc::Rc to alloc::rc::Arc? I think that's a breaking change as the Rc usages are on public-facing apis (structs and functions), and I don't know that we can make such a change without a major version bump.

I wonder what kind of benchmark hits this results in. How much slower is Arc than Rc in Pest?

[ekechinwokah]

Ah, got it. We haven't benchmarked.

[JohnDoeDoe]

Surely the argument holding this back is redundant. If someone activates the feature in their project which pollutes their full set of dependencies, they do so knowing they are in an async space to begin with.