code: protected function createCsrfCookie($token)
      {
          $options = $this->csrfCookie;
          return Yii::createObject(array_merge($options, [
              'class' => 'yii\web\Cookie',
              'name' => $this->csrfParam,
              'value' => $token,
          ]));
      }
docs: Creates a cookie with a randomly generated CSRF token.
  Initial values specified in [[csrfCookie]] will be applied to the generated cookie.
  @param string $token the CSRF token
  @return Cookie the generated cookie
  @see enableCsrfValidation