pocketmine\event\entity\ExplosionPrimeEvent::setBlockBreaking PHP Method

    public function setBlockBreaking($affectsBlocks)
    {
        $this->blockBreaking = (bool) $affectsBlocks;
    }

 public function onExplosionPrime(ExplosionPrimeEvent $event)
 {
     $event->setBlockBreaking(false);
 }