function domain_exists( $domain, $path, $network_id = 1 ) {
  $path   = trailingslashit( $path );
  $args   = array(
    'network_id'             => $network_id,
    'domain'                 => $domain,
    'path'                   => $path,
    'fields'                 => 'ids',
    'number'                 => 1,
    'update_site_meta_cache' => false,
  );
  $result = get_sites( $args );
  $result = array_shift( $result );

  
/**
 * Filters whether a site name is taken.
 *
 * The name is the site's subdomain or the site's subdirectory
 * path depending on the network settings.
 *
 * @since 3.5.0
 *
 * @param int|null $result     The site ID if the site name exists, null otherwise.
 * @param string   $domain     Domain to be checked.
 * @param string   $path       Path to be checked.
 * @param int      $network_id Network ID. Only relevant on multi-network installations.
 */
  return apply_filters( 'domain_exists', $result, $domain, $path, $network_id );
}