The current Gallery API executes a job until it reaches a completion state with either success or failure. Once reaching that state, the callout to /v1/jobs/{jobId}/ will return an array of messages that can then be parsed to gather information about the execution of the job, similar to the output you see in designer or via the CLI when running a job directly.
It would be nice if the callout to the jobs endpoint would constantly update and return the messages array with each callout. With jobs that take longer to execute, our Gallery API wrapper could then report back to us and let us know what messages have come out as the jobs runs. For example, if a process takes 2 hours to execute, we might want to know how far along the job is or if it has met a special condition that will cause it to run longer, etc. To do that, we could add in message tools that report info messages to us. Unfortunately, these messages are ineffective if we are running via the API because we won't see them until the job has fully completed.
