Listens for TCP connections on any available port number for both IPv6 and IPv4 (if each is available).
This is useful if you need to have a socket for incoming connections but don't care about the specific port number.
source_object will be passed out in the various calls to accept to identify this particular source, which is useful if you're
listening on multiple addresses and do different things depending on what address is connected to.
Optional Object identifying this source
the port number, or 0 in case of failure.