add types definition

[magic-akari]

[google-cla[bot]]

Thanks for your pull request. It looks like this may be your first contribution to a Google open source project (if not, look below for help). Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

:memo: Please visit https://cla.developers.google.com/ to sign.

Once you've signed (or fixed any issues), please reply here with @googlebot I signed it! and we'll verify it.

---

What to do if you already signed the CLA

Individual signers

• It's possible we don't have your GitHub username or you're using a different email address on your commit. Check your existing CLA data and verify that your email is set on your git commits.

Corporate signers

• Your company has a Point of Contact who decides which employees are authorized to participate. Ask your POC to be added to the group of authorized contributors. If you don't know who your Point of Contact is, direct the Google project maintainer to go/cla#troubleshoot (Public version).
• The email used to register you as an authorized contributor must be the email used for the Git commit. Check your existing CLA data and verify that your email is set on your git commits.
• The email used to register you as an authorized contributor must also be attached to your GitHub account.

ℹ️ Googlers: Go here for more info.

[magic-akari]

@googlebot I signed it!

[th0r]

Is there a chance this PR will be merged any time soon?

[xenji]

Hey, can anyone please review and merge this? Is none of the authors willing or able to review this? I'm aware, that this is a Labs project and thus does not receive the same attention as other projects. Still, you would help others when enabling people to contribute here.

[robertjcolley]

Should we submit this to DefinitelyTyped? I think we won't hear from the repo maintainers anytime soon and I would like to use these types. @magic-akari

https://github.com/DefinitelyTyped/DefinitelyTyped