This example features a minimalistic web server, that can only maintain a counter in a http session. It uses persistent connections of HTTP/1.1, and keeps one counter per connection. The session expires in $conn_timeout automatically.
Open two browsers (not just two windows/tabs of the same, browsers are smart now and share connections) and see how each has its own counter.
To install IO::Lambda, copy and paste the appropriate command in to your terminal.
perl -MCPAN -e shell
For more information on module installation, please visit the detailed CPAN module installation guide.