Using this:
<?php
// In a web application:
$event = new SyncEvent("GetAppReport");
$event->fire();
var_dump($event);
I get this:
object(SyncEvent)#1 (0) { }
You did remember to add the extension to your php.ini file? It won't load automagically, because I wasn't clever enough at the time I cobbled the tcz together to include an /usr/local/etc/php7/extensions/sync.ini file with it. Maybe I'll remember if I rebuild it for PHP 7.3.