Since we have total control over this 'started' metadata flag, we know it's always of type int and can simplify this code a bit.

Author: hostep

Storage/Meta.php

@@ -124,9 +124,9 @@ private function getStartTime(string $storageIdentifier): int
     {
         $metaData = $this->storage->read($storageIdentifier);
         if (!empty($metaData) && array_key_exists('started', $metaData)) {
-            assert(is_numeric($metaData['started']));
+            assert(is_int($metaData['started']));
 
-            return (int) $metaData['started'];
+            return $metaData['started'];
         }
 
         return 0;