Why does gRPC insist on trailers?

One of the major complaints people have with gRPC is that it requires HTTP trailers. Most people do not know this, but HTTP has had trailers in the specification since 1.1. Since HTTP/2 mandates TLS, it is unlikely middleboxes will error on unexpected trailers. We've only talked about if it's possible to use trailers, not if we should use them? It's been over two decades, and we haven't needed them yet, why put such a big risk into the gRPC protocol? The encoding of Protobuf probably had a hand in the need for trailers, because it's not obvious when a Proto is finished. It's not hard to imagine that trailers would be less of an issue, if the default encoding was JSON. The Final Nail in gRPC's Trailers. We could have modified the servers and clients to speak an updated version of the protocol that obviated the need for trailers.