code: func (s *grpcControllerServer) Shutdown(ctx context.Context, _ *plugin.Empty) (*plugin.Empty, error) {
  	resp := &plugin.Empty{}
  
  	// TODO: figure out why GracefullStop doesn't work.
  	s.server.Stop()
  	return resp, nil
  }
docs: // Shutdown stops the grpc server. It first will attempt a graceful stop, then a
  // full stop on the server.