Amp\Artax\IteratorWriter::write PHP Method

    public function write($socket, $iterator)
    {
        if (!$iterator->valid()) {
            return new Success();
        }
        $this->socket = $socket;
        $this->iterator = $iterator;
        $this->promisor = new Deferred();
        $this->writeNextElement();
        return $this->promisor->promise();
    }