Как выполнять одновременные запросы с помощью GuzzleHttp

Guzzle предоставляет fulfilled и rejected callabcks в пуле. здесь я выполнил тест по вашим значениям, подробнее читайте в Guzzle docs:

    $client = new Client([
        'http_errors'     => false,
        'connect_timeout' => 0.50, //////////////// 0.50
        'timeout'         => 1.00, //////////////// 1.00
        'headers' => [
          'User-Agent' => 'Test/1.0'
        ]
      ]);

$requests = function ($total) {
    $uris = [
        'https://httpbin.org/get',
        'https://httpbin.org/delay/1',
        'https://httpbin.org/delay/2',
        'https://httpbin.org/status/500',
        ];
    for ($i = 0; $i < count($uris); $i++) {
        yield new Request('GET', $uris[$i]);
    }
};

$pool = new Pool($client, $requests(8), [
    'concurrency' => 10,
    'fulfilled' => function ($response, $index) {
        // this is delivered each successful response
        print_r($index."fulfilled\n");
    },
    'rejected' => function ($reason, $index) {
        // this is delivered each failed request
        print_r($index."rejected\n");
    },
]);
// Initiate the transfers and create a promise
$promise = $pool->promise();
// Force the pool of requests to complete.
$promise->wait();

отклик

0fulfilled
3fulfilled
1rejected
2rejected

если вы хотите использовать свой код выше, вы также можете передать статус ответа в своих обещаниях $, вот пример:

use Psr\Http\Message\ResponseInterface;
use GuzzleHttp\Exception\RequestException;
....
$client = new Client([
    'http_errors'     => false,
    'connect_timeout' => 1.50, //////////////// 0.50
    'timeout'         => 2.00, //////////////// 1.00
    'headers' => [
      'User-Agent' => 'Test/1.0'
    ]
  ]);

            $promises = [
        'success' => $client->getAsync('https://httpbin.org/get')->then(
            function (ResponseInterface $res) {
                echo $res->getStatusCode() . "\n";
            },
            function (RequestException $e) {
                echo $e->getMessage() . "\n";
                echo $e->getRequest()->getMethod();
            }
        )
        ,
        'success' => $client->getAsync('https://httpbin.org/delay/1')->then(
            function (ResponseInterface $res) {
                echo $res->getStatusCode() . "\n";
            },
            function (RequestException $e) {
                echo $e->getMessage() . "\n";
                echo $e->getRequest()->getMethod();
            }
        ),
        'failconnecttimeout' => $client->getAsync('https://httpbin.org/delay/2')->then(
            function (ResponseInterface $res) {
                echo $res->getStatusCode() . "\n";
            },
            function (RequestException $e) {
                echo $e->getMessage() . "\n";
                echo $e->getRequest()->getMethod();
            }
        ),
        'fail500' => $client->getAsync('https://httpbin.org/status/500')->then(
            function (ResponseInterface $res) {
                echo $res->getStatusCode() . "\n";
            },
            function (RequestException $e) {
                echo $e->getMessage() . "\n";
                echo $e->getRequest()->getMethod();
            }
        ),
      ];

  $results = Promise\settle($promises)->wait();