[Feature Request]: Typescript async user functions

[dermasmid]

What would you like to happen?

from the docs, it looks like there in no support for async Dofn's https://beam.apache.org/documentation/sdks/typescript/#:~:text=TBD%20to%20do%20this%20for%20all%20user%20callbacks%20as%20well.

it might be a good idea to try to make pardo's process support async

beam/sdks/typescript/src/apache_beam/transforms/pardo.ts

Line 57 in e6e180b

process: (element: InputT, context: ContextT) => Iterable<OutputT> | void;

Issue Priority

Priority: 2 (default / most feature requests should be filed as P2)

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