@UnstableApi
    public GrpcServiceBuilder unframedGrpcErrorHandler(UnframedGrpcErrorHandler unframedGrpcErrorHandler) {
        requireNonNull(unframedGrpcErrorHandler, "unframedGrpcErrorHandler");
        this.unframedGrpcErrorHandler = unframedGrpcErrorHandler;
        return this;
    }
Set a custom error response mapper. This is useful to serve custom response when using unframed gRPC
service.
@param unframedGrpcErrorHandler The function which maps the error response to an {@link HttpResponse}.
grpc/src/main/java/com/linecorp/armeria/server/grpc/GrpcServiceBuilder.java