Como salvar permanentemente o arquivo carregado na tabela file_manged?

Como salvar um arquivo carregado com status igual a 1 na tabela file_managed, no Drupal 8?

Sempre que eu carrego um arquivo, ele é armazenado na tabela gerenciada por arquivo com o valor de status 0.
Eu usei File::load( $form_state->getValue('image'))para carregar o arquivo. O que preciso fazer a seguir?

No Drupal 7, eu usaria $file->status = FILE_STATUS_PERMANENT. Qual é o código equivalente para o Drupal 8?

class AddBannerForm extends FormBase {


public function getFormId()
{
  return 'add_banner_form';
}

public function buildForm(array $form, FormStateInterface $form_state)
{


  $form['image'] = array(
    '#type'          => 'managed_file',
    '#title'         => t('Choose Image File'),
    '#upload_location' => 'public://images/',
    '#default_value' => '',
    '#description'   => t('Specify an image(s) to display.'),
    '#states'        => array(
      'visible'      => array(
        ':input[name="image_type"]' => array('value' => t('Upload New Image(s)')),
      ),
    ),
  );

  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Save image'),
  );

  return $form;
}


public function validateForm(array &$form, FormStateInterface $form_state)
{
    File::load( $form_state->getValue('image') );
}


public function submitForm(array &$form, FormStateInterface $form_state)
{

}
}

Obrigado @Clive & @kiamlaluno

/* Fetch the array of the file stored temporarily in database */ 
   $image = $form_state->getValue('image');

/* Load the object of the file by it's fid */ 
   $file = File::load( $image[0] );

/* Set the status flag permanent of the file object */
   $file->setPermanent();

/* Save the file in database */
   $file->save();

Use este código para salvar a imagem permanentemente no formulário de configuração, se você estiver usando o Drupal 8.

public function submitForm(array &$form, FormStateInterface $form_state) {
  parent::submitForm($form, $form_state);
  $image = $form_state->getValue('welcome_image');
  // Load the object of the file by its fid. 
  $file = File::load($image[0]);
  // Set the status flag permanent of the file object.
  if (!empty($file)) {
    $file->setPermanent();
    // Save the file in the database.
    $file->save();
    $file_usage = \Drupal::service('file.usage'); 
    $file_usage->add($file, 'welcome', 'welcome', \Drupal::currentUser()->id());
  }
  $config = $this->config('welcome.settings');
  $config->set('welcome_text', $form_state->getValue('welcome_text'))
    ->set('welcome_image', $form_state->getValue('welcome_image'))
    ->save();
}