[mcqueenjordan]

The underlying protocol is not necessarily HTTP.

[staticassertion]

I think it is necessarily HTTP/2, but would be happy to learn I'm mistaken - it's not something I'm overly confident about.

https://developers.googleblog.com/2015/02/introducing-grpc-n...

[rezonant]

gRPC uses HTTP/2.0 yes, so headers are a concept, but imagine taking it one step further, for instance using WebSockets. There is no concept of headers within an individual WebSocket message, so it would need to be encapsulated in an application-specific way anyway.