The README in our client libraries doesn't provide a document for how to customize client library's behavior (timeout, retry, etc). I suggest we add a link to the Client Library Howto in the READMEs (if that document is not permanent, we can use a specific commit hash).

Here's a draft:

This library is built on top of google-gax. To customize the common behavior of this client library (timeout, retry, etc), see Client Library Howto.