1. spec compliance, as we are implementing the new grpc-web spec in nginx at the same time
2. feature parity, e.g. CORS, URL white-listing
3. discuss when/whether to add this proxy to grpc-contrib, in addition to the existing go-gateway, e.g. does the proxy support non-grpc-web features etc?

https://github.com/improbable-eng/grpc-web/tree/master/go/grpcweb

@zinuga
@mwitkow