Coalesce pending asynchronous tasks

Related Projects Swift Async Algorithms
1

Hi! I have an asynchronous task that performs expensive operations. I have the following requirements:

  • There must be at most one of these tasks running at a time.
  • Pending tasks may be added multiple times while a running task is still executing.
  • Pending tasks should be coalesced into a single pending task, merging the requests into a single request.

Is it possible to model this using the existing AsyncSequence algorithms? If not, what new algorithms would we need to introduce in order to satisfy these requirements?

2

Maybe an AsyncBufferSequence with a new AsyncBufferSequencePolicy that supports coalescing?

let pendingRequests = requests.buffer(policy: .coalescing({ (existing, new) in
  return merge(existing, new)
}))

Or just a new AsyncCoalescingSequence? :thinking:

let pendingRequests = requests.coalesced { (existing, new) in
  return merge(existing, new)
}