performMetaRefresh example

    $this->config('system.logging')->set('error_level', ERROR_REPORTING_HIDE)->save();

    $this->drupalLogin($this->rootUser);
    $this->assertSessionCookieExists(TRUE);
    $this->assertBigPipeNoJsCookieExists(FALSE);

    // By calling performMetaRefresh() here, we simulate JavaScript being     // disabled, because as far as the BigPipe module is concerned, it is     // enabled in the browser when the BigPipe no-JS cookie is set.     // @see setUp()     // @see performMetaRefresh()     $this->performMetaRefresh();
    $this->assertBigPipeNoJsCookieExists(TRUE);

    $this->drupalGet(Url::fromRoute('big_pipe_test'));
    $this->assertBigPipeResponseHeadersPresent();
    $this->assertSession()->responseHeaderNotContains('X-Drupal-Cache-Tags', 'cache_tag_set_in_lazy_builder');

    $this->setCsrfTokenSeedInTestEnvironment();
    $cases = $this->getTestCases();
    $this->assertBigPipeNoJsPlaceholders([
      $cases['edge_case__invalid_html']->bigPipeNoJsPlaceholder           => $cases['edge_case__invalid_html']->embeddedHtmlResponse,
      $cases['html_attribute_value']->bigPipeNoJsPlaceholder              => $cases['html_attribute_value']->embeddedHtmlResponse,