ChildStepsModule

Starts another workflow and gives its handle once the child's start is stored. The child's ID is this workflow's ID, a colon, and this step's path, so a repeated start after a crash reaches the same child and does not start a second one. A child that is never awaited runs on by itself and outlives this workflow. If this workflow is cancelled while the start is in flight, the child is cancelled too. The child's workflow must be registered with `Workflows.register` in the same process.

Waits for a child workflow to end and gives its result. A child that faulted or was cancelled fails this step with `ChildFaulted`, and a result this step's type cannot read fails it with `NotRetryable`. If this workflow is cancelled while it waits, the child is cancelled too.

Starts a child workflow and waits for its result.