pub async fn unmatched_route(headers: HeaderMap) -> Response<Body>Expand description
Answers a request that matched no route, in the protocol the caller used.
gRPC callers get the UNIMPLEMENTED status they expect, and everyone else gets a plain 404 Not Found.
Answering a gRPC caller with a bare 404 would mostly work – the gRPC specification has clients map 404 to
UNIMPLEMENTED when no grpc-status is present – but it costs nothing to return the status directly, and doing so
keeps the response identical to what a standalone gRPC server would send.