Title: Envoy's grpc-json transcoder

Description:

I've a REST client and a gRPC server and I'm using Envoy's grpc-json transcoder.
When an exception is thrown by gRPC server with gRPC error code and gRPC error message,
on the client side I receive corresponding HTTP error status code (grpc-error-code converted to http error code) and error message like "Invalid userid" is set in response header "grpc-message".
Now I want gRPC error message to appear in body rather than response header. Is it possible with Envoy? If yes, How can I do it?