Documentation for method listen assembled from the following pages:

Class: IO::Socket::Async §

From IO::Socket::Async

(IO::Socket::Async) method listen §

method listen(Str $host, Int $port --> Supply)

Creates a listening socket on the specified $host and $port, returning a Supply to which the accepted client IO::Socket::Asyncs will be emitted. This Supply should be tapped start listening for client connections. You can set $port to 0 if you want the operating system to find one for you.

The IO::Socket::Async::ListenSocket returned by calling the tap method on the supply returned represents the underlying listening TCP socket, which can be closed using its close method. If $port was set to 0, you can get the port the socket ended up with using its socket-port method.