pocketmine\entity\Entity::resetFallDistance PHP Method

    public function resetFallDistance()
    {
        $this->fallDistance = 0;
    }

 public function onEntityCollide(Entity $entity)
 {
     $entity->resetFallDistance();
     if ($entity->fireTicks > 0) {
         $entity->extinguish();
     }
     $entity->resetFallDistance();
 }