[aktau]

I've been trying to read the HTTP2 spec and I can't figure out whether it's allowable to return or modify the HTTP(2) status code in a trailer instead of in the header.

After some re-readings, I decided it wasn't allowed.

But then, gRPC definitely needs to be able to signal an error even after it has already streamed data. So gRPC would need to use some end-of-connection message, like a trailer.