Notifications Center uses keruald/broker as an abstraction
layer to use a broker.

To connect to RabbitMQ, this library uses php-amqplib.
Recent php-amqplib versions uses the sockets extension.

It appears constants like SOCKET_EAGAIN are now defined
in the sockets extension.

Reference: https://github.com/php-amqplib/php-amqplib/issues/608

Ref T1800

Build on Dwellers

php -i gives Sockets Support => enabled