Kraken\Ipc\Zmq\ZmqBuffer::handleWriteEvent PHP Method

    public function handleWriteEvent()
    {
        foreach ($this->messages as $i => $message) {
            try {
                $message = (array) $message;
                $sent = (bool) $this->socket->sendmulti($message, ZMQ::MODE_DONTWAIT);
                unset($this->messages[$i]);
                if (0 === count($this->messages)) {
                    $this->loop->removeWriteStream($this->fd);
                    $this->listening = false;
                    $this->emit('end');
                }
            } catch (ZMQSocketException $ex) {
                $this->emit('error', [$ex]);
            }
        }
    }

 /**
  * Handle ZMQ Event.
  */
 public function handleEvent()
 {
     while ($this->socket !== null) {
         $events = $this->socket->getSockOpt(ZMQ::SOCKOPT_EVENTS);
         $hasEvents = $events & ZMQ::POLL_IN || $events & ZMQ::POLL_OUT && $this->buffer->listening;
         if (!$hasEvents) {
             break;
         }
         if ($events & ZMQ::POLL_IN) {
             $this->handleReadEvent();
         }
         if ($events & ZMQ::POLL_OUT && $this->buffer->listening) {
             $this->buffer->handleWriteEvent();
         }
     }
 }