pocketmine\level\Level::addEntityMotion PHP Method

    public function addEntityMotion(int $chunkX, int $chunkZ, int $entityId, float $x, float $y, float $z)
    {
        if (!isset($this->motionToSend[$index = Level::chunkHash($chunkX, $chunkZ)])) {
            $this->motionToSend[$index] = [];
        }
        $this->motionToSend[$index][$entityId] = [$entityId, $x, $y, $z];
    }