sync exemple of scrip

sync.php

<?php

$names = [];

$add = function($str) use(&$names)
{
     sleep(10);
     array_push($names, $str);

     return $str;
};


var_dump($names); // array(0) { }
echo $add('Gustavo'); // Gustavo
var_dump($names); // array(1) { [0]=> string(7) "Gustavo" }