[feat] Move async workflows to AsyncGuard class

[zsimjee]

Description [Add a description of the feature]

Why is this needed [If you have a concrete use case, add details here.]

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Maintaining compatability

one risk with creating a parallel async-guard class is that we need to maintain parity longterm. The validator test harness is meant to do this, with the current sync/async etc versions of guard with each validator. We should migrate this harness as well once this async-guard class is created.