Build a pluggable HTTP system around Guzzle Promises

[skyzyx]

• https://github.com/guzzle/guzzle
• https://github.com/illuminate/http
• https://book.cakephp.org/3.0/en/core-libraries/httpclient.html
• https://github.com/kriswallsmith/Buzz
• https://github.com/symfony/http-client
• https://github.com/zendframework/zend-psr7bridge
• https://github.com/clue/reactphp-buzz

[skyzyx]

These support async, which is always preferable.

• https://github.com/WyriHaximus/react-guzzle-psr7
• https://github.com/clue/reactphp-buzz
• https://reactphp.org/http-client/
• https://www.swoole.co.uk/docs/modules/swoole-async-http-client