Match a result to a request when sending multiple requests. ref 1: http://stackoverflow.com/questions/22649888/how-to-match-a-result-to-a-request-when-sending-multiple-requests

multipleRequest.php

<?php

use GuzzleHttp\Event\CompleteEvent;
use GuzzleHttp\Event\ErrorEvent;
use GuzzleHttp\Client;
use GuzzleHttp\Pool;

$urls = ['http://www.google.com', 'http://www.facebook.com']

$client = new Client([
            'verify' => false,
        ]);

$allResults = [];
$requests = [];
foreach ($urls as $url) {
    $requests[] = $client->createRequest('GET', $url, [
        'verify' => false,
        'headers' => ['User-Agent' => 'Mozilla/5.0'],
        'events' => [
            'complete' => function (CompleteEvent $e) use (&$allResults, $url){
                $response = $e->getResponse();
                $allResults[$url] = $response;
            },
            'error' => function (ErrorEvent $e) use (&$allResults, $url){
                $exception = $e->getException();
                $allResults[$url] = $exception;
            }
        ]
    ]);
}
// Results is a GuzzleHttp\BatchResults object.
$results = Pool::batch($client, $requests);

/** @var \GuzzleHttp\Message\ResponseInterface $response */
if (isset($allResults[$url]) && ($response = $allResults[$url]) && ($response instanceof \GuzzleHttp\Message\ResponseInterface)) {
    $content = $response->getBody();
} elseif ($response instanceof \GuzzleHttp\Exception\ConnectException) {
    /** @var \GuzzleHttp\Exception\ConnectException $response */
    $exceptionMessage = $response->getMessage();
}

?>