How to write my cookies to browsers?

[Michael2008S]

Where I can write my cookies to browser ?

func (s *Service) Auth(c context.Context, req *iam.AuthReq) (*iam.AuthResp, error) {
	if err := req.Validate(); err != nil {
		return nil, err
	}

	dbCtx := s.db.WithContext(c)

	usr, err := s.udb.FindByAuth(dbCtx, req.Auth)
	if err != nil {
		return nil, invalidUserPW
	}

	if !s.sec.MatchesHash(usr.Password, req.Password) {
		return nil, invalidUserPW
	}

	token, err := s.tg.GenerateToken(&guidecentury.AuthUser{
		ID:       usr.ID,
		TenantID: usr.TenantID,
		Username: usr.Username,
		Email:    usr.Email,
		Role:     guidecentury.AccessRole(usr.RoleID),
	})

	if err != nil {
		return nil, err
	}

	uToken := xid.New().String()

	usr.UpdateLoginDetails(uToken)

	if err = s.udb.UpdateLastLogin(dbCtx, usr); err != nil {
		return nil, err
	}

	// Todo Write my cookies to browsers?


	return &iam.AuthResp{
		Token:        token,
		RefreshToken: uToken,
	}, nil
}

And how I write my cookies?