HttpMethod httpMethod() {
            // Only one HTTP method can be specified for the route specified by gRPC transcoding.
            return spec.route().methods().stream().findFirst().get();
        }
{@link DocServicePlugin} implementation that supports {@link GrpcService}s.
grpc/src/main/java/com/linecorp/armeria/internal/server/grpc/GrpcDocServicePlugin.java