Connect a (client) socket to Address and return a 
bi-directional connection through the stream-handles Read and Write. 
This predicate may be hooked by defining socket:tcp_connect_hook/4 
with the same signature. Hooking can be used to deal with proxy 
connections. E.g.,
:- multifile socket:tcp_connect_hook/4.
socket:tcp_connect_hook(Socket, Address, Read, Write) :-
    proxy(ProxyAdress),
    tcp_connect(Socket, ProxyAdress),
    tcp_open_socket(Socket, Read, Write),
    proxy_connect(Address, Read, Write).
- deprecated
- New code should use tcp_connect/3 
called as
tcp_connect(+Address, -StreamPair, +Options).