Add Support for async Origin Function

[captbunzo]

What is the problem this feature would solve?

It would be useful if origin functions could be defined asynchronously.

What is the feature you are proposing to solve the problem?

Modification of the code to allow asynchronous origin functions.

What alternatives have you considered?

No response

[Arbarwings]

@SaltyAom Any chance we could get the PR for this feature merged? It would be great to have it included.