require __DIR__ . '/../vendor/autoload.php';

use GuzzleHttp\Client;
use GuzzleHttp\Exception\RequestException;
use GuzzleHttp\Pool;
use GuzzleHttp\Psr7\Request;
use GuzzleHttp\Psr7\Response;
use Psr\Http\Message\ResponseInterface;

$client = new Client();

$requests = static function ($total) {
    for ($i = 1; $i < $total; $i++) {
        yield $i => new Request('GET', 'http://httpbin.org/redirect/' . $i);
    }
};

$pool = new Pool($client, $requests(5), [
    'concurrency' => 5,
    'options' => [
        'fulfilled' => function (Response $response, $index) {
            // this is delivered each successful response
            var_dump($index);
        },
        'rejected' => function (RequestException $reason, $index) {
            // this is delivered each failed request
            var_dump($index);
        },
        'on_headers' => static function (ResponseInterface $response, Request $request) {
            var_dump((string)$request->getUri());
        },
    ],
]);

// Initiate the transfers and create a promise
$promise = $pool->promise();

// Force the pool of requests to complete.
$promise->wait();