set_changeset_lock example

            // If no changeset UUID has been set yet, then generate a new one.             if ( empty( $changeset_uuid ) ) {
                $changeset_uuid = wp_generate_uuid4();
            }

            $this->_changeset_uuid = $changeset_uuid;
        }

        if ( is_admin() && 'customize.php' === $pagenow ) {
            $this->set_changeset_lock( $this->changeset_post_id() );
        }
    }

    /** * Callback to validate a theme once it is loaded * * @since 3.4.0 */
    public function after_setup_theme() {
        $doing_ajax_or_is_customized = ( $this->doing_ajax() || isset( $_POST['customized'] ) );
        if ( ! $doing_ajax_or_is_customized && ! validate_current_theme() ) {