Why is _state prefixed with an underscore? Is it not intended for use?

I'm writing an application where, given a job ID, I want to check whether a job has completed or not. The obvious way would to get the job and check its state, but I noticed that the property is called `_state` which usually indicates a private property, so I'm thinking maybe I'm doing something wrong?

No file, test, or entry point is named. Start by locating Kue's job-state API and its documentation, then determine whether `_state` is an intended public interface or whether a supported accessor exists. Done means the supported way to check completion is clearly documented, with an example if the project’s documentation conventions allow it.

Written by the indexing model from the issue text.