The Cloud KMS team received a customer question about how to authenticate using a service account key file. It took us a while to figure out what to recommend, especially because the relevant clientOptions property is three levels up the inheritance hierarchy, and the docs for clientOptions aren't linked from the generated client-specific doc.

Can we consider adding some samples of different authentication workflows? It feels like the overall authentication using client libraries topic could be fleshed out quite a bit to cover all the formerly-silver languages, and include samples that use key files.