setTimeout for php

settimeout.php

<?php
class TimeoutClass extends Thread {
  public function __construct(callable $cb, int $time, $args){
    $this->callback = $cb;
    $this->args = $args;
    $this->time = $time * 1000;
  }

  public function run(){
    usleep($this->time);
    ($this->callback)(...$this->args);
  }
}

function setTimeout($cb, $time, ...$args){
  static $count = 0;
  $id = "timeout$count";
  $GLOBALS[$id] = new TimeoutClass($cb, $time, $args);
  $GLOBALS[$id]->start();
  $count++;
}

//Basic usage
setTimeout(function(){
  echo "Timeout has ended\n";
}, 2000);

//Passing arguments
setTimeout(function($x, $y){
  echo "Passed $x and $y\n";
}, 2000, 25, 34);

->start()

WTF?? where it