[wordpress] Debug switch_to_blog snippet

filter.php

<?php 

\add_action('switch_blog', function ($new_blog_id, $prev_blog_id, $context) {
     error_log("Switch! {$prev_blog_id} -> {$new_blog_id}. Context: {$context}");
     if (count($GLOBALS['_wp_switched_stack']) > 1) {
         error_log('Catch anomaly with _wp_switched_stack!');
         $e = new \Exception;
         error_log($e->getTraceAsString()));
     }
 }, 10, 3);