public GrpcServiceBuilder addServices(Iterable<BindableService> bindableServices) {
        requireNonNull(bindableServices, "bindableServices");
        bindableServices.forEach(this::addService);
        return this;
    }
Adds gRPC {@link BindableService}s to this {@link GrpcServiceBuilder}. Most gRPC service
implementations are {@link BindableService}s.
grpc/src/main/java/com/linecorp/armeria/server/grpc/GrpcServiceBuilder.java