Magically take care of efficient discovery doc retrieval, please.

[SurferJeffAtGoogle]

It's easy to post an app on app engine that makes too many calls to the discovery doc service and gets throttled. I think the code in this library will suffer the same fat. More details here:

https://cloud.google.com/appengine/articles/efficient_use_of_discovery_based_apis

[dhermes]

@SurferJeffAtGoogle Thanks for pointing that out. I am the author of that document :)

We don't use discovery docs (at least not yet), but will keep an eye out! Thanks

[SurferJeffAtGoogle]

Cool. Thanks!