For every requestSync or reportState request, a new JWTClient is created, causing a post request to get a new token:

The token that is returned is valid for an hour, but the client and token are still recreated for every request.

I suggest creating the JWTClient just once, on first use, this causes that the token is cached and only refreshed when it is no longer valid.

Furthermore, during the request of a new token, all other requests should wait for this token to finish loading instead of starting a new load.

This will drastically improve the performance and lower the number of requests to the Google Authentication API.

I can create a PR if this is approved.