There would not be anything magic about an async function or actor returning a Result<S,F> -- you'd simply be returning that value (result) asynchronously.
We do not anticipate magically converting swift code that is an async function returning result into anything else. The story is different with existing Objective C APIs where the importer can do things, but since you mention Result I don't think you mean the obj-c interop story. The obj-c part has it's own proposal though if that's what you meant @masters3d.
The "future"-like type in this proposal is Task.Handle.
You can read more about in the [Concurrency] Structured concurrency - #125 by ktoso proposal (check out the github version for the latest wording: https://github.com/DougGregor/swift-evolution/blob/structured-concurrency/proposals/nnnn-structured-concurrency.md