Motivation

Developers use the callback pattern to trigger operations and notify the caller asynchronously that the triggered operation finished. Callback is a method which sends the results of the long-running operation to the client when the results are finally ready.

Goal

Enable use of callback states in workflows

Scenarios

As a developer, I need to callback a workflow via an event with results of a long-running operation so that the workflow service doesn’t actively wait ( and doesn’t actively pull the results ).

Expected outcomes

Workflows can define callback states with an action and callback event

HTTP callbacks are out of scope of this requirement (tracked separately, will be possible via operation state and OpenAPI calls)