add hook for http requests

There's no good way to count read and write requests (e.g. for the sheets v4 api) - which is rate limited.

If this gem allowed the configuration of a lambda for when a http request is made, then the application using this gem would be free to log/count requests and then mitigate over usage.

As it stands now it's a bit of craps shoot. No way to tell when the client is reaching its quota.

No file or test is named. Start by locating the gem’s HTTP request entry point and tracing how requests are issued; determine where a configurable callback belongs and what request details it must expose. Done means applications can observe requests reliably and tests cover the callback behavior.

Vom Indexierungsmodell aus dem Issue-Text verfasst.