custom rest-api endpoint wordpress

<?php
/**
* Plugin Name: API Plugin
* Plugin URI: https://www.google.com
* Description: Test
* Version: 1.0
* Author: Test
* Author URI: https://www.google.com
*/

function trying() {
	return "Hi";
}

add_action('rest_init_api', function() {
	register_rest_route('custom/v1/', 'test', [
			'methods' => 'GET',
			'callback' => 'trying',
	]);
});