Executor Service with Parallel and Channels

example.php

<?php
use \parallel\{Runtime, Channel};

class ExecutorService {

    public function __construct(int $workers, string $channel = __CLASS__, int $backlog = Channel::Infinite) {
        if ($backlog == 0) {
            /*
            * execute() will block until a worker is ready
            */
            $this->channel = Channel::make($channel);
        } else {
            /*
            * execute() will not block (until backlog is reached)
            */
            $this->channel = Channel::make($channel, $backlog);
        }

        for ($worker = 0; $worker < $workers; $worker++) {
            $this->workers[$worker] = new Runtime;
            $this->workers[$worker]->run(
                Closure::fromCallable(
                    [self::class, "__thread"]),
                    [(string)$this->channel]);
        }
    }

    private static function __thread(string $channel) {
        $channel = Channel::open($channel);

        while (($job = $channel->recv())) {
            /*
            * Missing try {} for simplicity
            */
            ($job["function"])(...$job["argv"]);
        }
    }

    public function execute(Closure $closure, array $argv) {
        $this->channel->send([
            "function" => $closure,
            "argv"     => $argv
        ]);
    }

    public function __destruct() {
        /*
        * Notify workers to shutdown
        */
        foreach ($this->workers as $worker) {
            $this->channel->send(false);
        }

        /*
        * Close workers
        */
        foreach ($this->workers as $worker) {
            $worker->close();
        }

        /*
        * Close channel
        */
        $this->channel->close();
    }
}

$executor = new ExecutorService(4);

while (++$i<1000) {
    $executor->execute(function($i){
        printf("{$i}: Hello from #%d\n", 
            zend_thread_id());
    }, [$i]);
}
?>