Backdrop Test

backdrop-test.php

<?php 

function exp_add_notifications( $post_id, $post ) {

	if ( 'auto-save' == $post->post_status || 'auto-draft' == $post->post_status ) {
		return;
	}

	$message = get_the_title( $post_id ) . ' was added.';

	$task = new \HM\Backdrop\Task( 'exp_send_notifications', $message );
	$task->schedule();

}
add_action( 'publish_topic', 'exp_add_notifications', 10, 2 );

function exp_send_notifications( $message ) {

	$users = new WP_User_Query( array( 'role' => 'Subscriber' ) );

	if ( ! empty( $users ) ) {

		foreach ( $users as $user ) {
			exp_add_notification( $user->ID, $message );
		}
	}

}