Need to ensure we use lower-case gRPC header keys

[omaray]

This might be a no-op, but please double check. Filing this issue just in case.

We need to ensure that all headers used for gRPC are written in lower-case. Please review this Pull Request for reference of what needs to be updated.

Again, perhaps this doesn't apply to your language. Feel free to comment and close the issue (after you double checking).

[broady]

Yup, handled by grpc-go.

@omaray, you should probably file these bugs against the gRPC library rather than users of gRPC. gRPC should handle this automatically, or at least return an error if the header keys are not lowercased.