In our demo repo for workflow a nice addition would be a workflow triggering another workflow and then monitoring it through the Data Index API.

The triggered workflow would just log a message, wait for some time and then exit.
In order to demonstrate success/error check, an input argument could be indicating if the workflow should end in error or not.
Similarly, it would be nice for the main workflow to parse the output and use it in some way (just log a message and/or include it in its own result)