Sleep() alternative

When i use Sleep() in my Plugin, the whole server "sleeps". How can i fix that? Here is my Code.

PHP:

<?php

namespace derdumme\info;

use pocketmine\plugin\PluginBase;
use pocketmine\event\Listener;
use pocketmine\utils\TextFormat;
use pocketmine\event\player\PlayerJoinEvent;

class info extends PluginBase implements Listener {
  public function onEnable() {
  $this->getLogger()->info(TextFormat::GREEN."wurde aktiviert.");
  $this->getServer()->getPluginManager()->registerEvents($this, $this);
  }
  public function onDisable() {
  $this->getLogger()->info(TextFormat::RED."wurde deaktiviert.");
  }
  public function onJoin(PlayerJoinEvent $event){
  while(true) {
  $message = random_int(1, 5);
  if($message == 1){
  $event->getPlayer()->sendPopup(TextFormat::GREEN."Teamspeak-Server: ts.skyzonemc.net");
  } elseif ($message == 2) {
  $event->getPlayer()->sendPopup(TextFormat::GOLD."Website: SkyZoneMC.net");
  } elseif ($message == 3) {
  $event->getPlayer()->sendTip("This is a Tip");
  }
  sleep(60);
  }
  }
   
   

}



Well, what do you even want to do? (I don't see a reason for the while and the sleep)
Also, please post this on the new forums.

This thread has been continued on https://forums.pmmp.io/threads/sleep-alternative.203