REST API to get process result

Summary

How do I fetch result of a process instance via REST? For eg: result parameter defined in message end activity.

Content

I have a process which instantiates multiple instances of subprocesses based on an array input. The subprocess returns a result array that I pass to message end activity in the main process. I want access to this result array via REST APIs. But I couldn't find any API for this in https://docs.oracle.com/en/cloud/paas/process-cloud/cprrb/index.html

Is there any other way to get to this?

Version

19.2.1.0.0