code: func readBuildSecrets(ctx context.Context) (*pb.BuildSecrets, error) {
  	swarming := lucictx.GetSwarming(ctx)
  	if swarming == nil {
  		return nil, nil
  	}
  
  	secrets := &pb.BuildSecrets{}
  	if err := proto.Unmarshal(swarming.SecretBytes, secrets); err != nil {
  		return nil, err
  	}
  	return secrets, nil
  }
docs: // readBuildSecrets reads BuildSecrets message from swarming secret bytes,
  // if any.