aws-sdk-php: InstanceProfileProvider: bug with Guzzle 7.0.1, works with 6.4.5

Confirm by changing [ ] to [x] below to ensure that it’s a bug:

• I’ve gone though Developer Guide and API reference
• I’ve checked AWS Forums and StackOverflow for answers
• I’ve searched for previous similar issues and didn’t find any solution

Describe the bug S3Client used in the context of InstanceProfilePovider. The description is the same as #2022 Aws\Exception\CredentialsException Timeout, but it fails only with guzzlehttp/guzzle v7.0.1. The same SDK version on same instance (and same application) with guzzlehttp/guzzle v 6.5.4 works fine. Therefore I don’t think that the issue is the EC2 instance being unable to respond quick enough.

Version of AWS SDK for PHP? v3.138.9 (but I believe it’s the same with 3.145)

Version of PHP (php -v)? php 7.4

To Reproduce (observed behavior)

When running this code on an EC2 instance with an IAM role granting the appropriate S3 permissions:

$client = new S3Client([
    'version' => 'latest',
    'region' => 'us-east-1,
]);

$client->getObject([
  'Bucket' => $bucket,
  'Key' => $key,
  'SaveAs' => $localFilename,
]);

with the Guzzlehttp version reported above (7.0.1): I get an exception:

Aws\\Exception\\CredentialsException
Code: 0
Message: Error retrieving credentials from the instance profile metadata service. (cURL error 28: Operation timed out after 1000 milliseconds with 0 bytes received (see https://curl.haxx.se/libcurl/c/libcurl-errors.html))
File: /srv/app/vendor/aws/aws-sdk-php/src/Credentials/InstanceProfileProvider.php
Line: 226
Trace:
#0 /srv/app/vendor/guzzlehttp/promises/src/Promise.php(203): Aws\\Credentials\\InstanceProfileProvider->Aws\\Credentials\\{closure}()
#1 /srv/app/vendor/guzzlehttp/promises/src/Promise.php(156): GuzzleHttp\\Promise\\Promise::callHandler()
#2 /srv/app/vendor/guzzlehttp/promises/src/TaskQueue.php(47): GuzzleHttp\\Promise\\Promise::GuzzleHttp\\Promise\\{closure}()
#3 /srv/app/vendor/guzzlehttp/guzzle/src/Handler/CurlMultiHandler.php(155): GuzzleHttp\\Promise\\TaskQueue->run()
#4 /srv/app/vendor/guzzlehttp/guzzle/src/Handler/CurlMultiHandler.php(182): GuzzleHttp\\Handler\\CurlMultiHandler->tick()
#5 /srv/app/vendor/guzzlehttp/promises/src/Promise.php(246): GuzzleHttp\\Handler\\CurlMultiHandler->execute()
#6 /srv/app/vendor/guzzlehttp/promises/src/Promise.php(223): GuzzleHttp\\Promise\\Promise->invokeWaitFn()
#7 /srv/app/vendor/guzzlehttp/promises/src/Promise.php(267): GuzzleHttp\\Promise\\Promise->waitIfPending()
#8 /srv/app/vendor/guzzlehttp/promises/src/Promise.php(225): GuzzleHttp\\Promise\\Promise->invokeWaitList()
#9 /srv/app/vendor/guzzlehttp/promises/src/Promise.php(62): GuzzleHttp\\Promise\\Promise->waitIfPending()
#10 /srv/app/vendor/guzzlehttp/promises/src/Coroutine.php(65): GuzzleHttp\\Promise\\Promise->wait()
#11 /srv/app/vendor/guzzlehttp/promises/src/Promise.php(246): GuzzleHttp\\Promise\\Coroutine->GuzzleHttp\\Promise\\{closure}()
#12 /srv/app/vendor/guzzlehttp/promises/src/Promise.php(223): GuzzleHttp\\Promise\\Promise->invokeWaitFn()
#13 /srv/app/vendor/guzzlehttp/promises/src/Promise.php(62): GuzzleHttp\\Promise\\Promise->waitIfPending()
#14 /srv/app/vendor/guzzlehttp/promises/src/Coroutine.php(85): GuzzleHttp\\Promise\\Promise->wait()
#15 /srv/app/vendor/guzzlehttp/promises/src/Promise.php(273): GuzzleHttp\\Promise\\Coroutine->wait()
#16 /srv/app/vendor/guzzlehttp/promises/src/Promise.php(225): GuzzleHttp\\Promise\\Promise->invokeWaitList()
#17 /srv/app/vendor/guzzlehttp/promises/src/Promise.php(62): GuzzleHttp\\Promise\\Promise->waitIfPending()
#18 /srv/app/vendor/aws/aws-sdk-php/src/AwsClientTrait.php(59): GuzzleHttp\\Promise\\Promise->wait()
#19 /srv/app/vendor/aws/aws-sdk-php/src/AwsClientTrait.php(87): Aws\\AwsClient->execute()

** Expected behaviour**

Exact same code, same machine, works fine if I downgrade guzzlehttp/guzzle to version 6.5.4.