This release has two major improvements. The first one is that react/dns
is now using a promise based API. In case you missed it, react/promise is a PHP library for promises. Take a look at the README and familiarize yourself with it, as it will be used by many libs in the react ecosystem, including core.
The previous API was:
$dns->resolve('igor.io', function ($ip) {
echo "Yay, the IP is $ip.\n";