We need to investigate the new poll_api from PHP/8.6

The poll_api can benefit Workerman, without use any external extensions.

PHP 8.6 is now in beta.

More info:

• https://wiki.php.net/rfc/poll_api
• https://stitcher.io/blog/new-in-php-86
• https://phpbenchlab.com/php-8-6-new-features-deep-dive/