guzzle / promises

# Guzzle Promises
`guzzlehttp/promises` is a small promise library used by Guzzle for asynchronous
operations. It implements promise chaining, synchronous waiting, cancellation,
and helpers for working with groups of promises.
Most application developers use this package through
`guzzlehttp/guzzle` by
calling methods such as `requestAsync()`. Install this package directly when you
need promise composition without the full HTTP client.
## Installation
 [code] 
## Version Guidance
| Version | Status | PHP Version |
|---------|--------------|--------------|
| 3.1 | Latest | >=7.4, =7.2.5, =5.5, then(
 function ($value) {
 echo 'Fulfilled: ' . $value;
 },
 function ($reason) {
 echo 'Rejected: ' . $reason;
 }
);
$promise->resolve('done');
Utils::queue()->run();
 [code] php
$value = $promise->wait();
 [code] php
$promise = $client->requestAsync('GET', 'https://example.com');
$response = $promise->wait();
```
## Documentation
- Promise Quick Start
- Promise API
- Promise Interoperability
- Implementation Notes
- Upgrade Guide
- Changelog
## Security
If you discover a security vulnerability within this package, please send an
email to security@tidelift.com. All security vulnerabilities will be promptly
addressed by the security maintainers listed in the
Security Policy. Please do
not disclose security-related issues publicly until a fix has been announced.
## License
Guzzle is made available under the MIT License (MIT). Please see
License File for more information.
## For Enterprise
Available as part of the Tidelift Subscription
The maintainers of Guzzle and thousands of other packages are working with
Tidelift to deliver commercial support and maintenance for the open source
dependencies you use to build your applications. Save time, reduce risk, and
improve code health, while paying the maintainers of the exact dependencies you
use.
Learn more.