Allow accessing encapsulated task state

[chancancode]

See machty/ember-concurrency#362

[github-actions]

Hello @chancancode!

I see that you have opened a pull request against the "master" branch. We are in the process of renaming the "master" branch to "main" in this repository.

⚠️ The "master" branch is deprecated and will be removed from this repository in the future.

Please migrate your local repository by renaming the "master" branch to "main":

$ cd my-git-project
$ git checkout master
$ git branch -m main
$ git branch -u origin/main

Please also set the base branch for this pull request to "main" instead of "master". For more information on how to do this, refer to this GitHub support article.