Set up listeners in config/sys.config.
Use prometheus_ranch_example_client to communicate.
Assuming you have a listener named tcp_echo running, which echoes back
everything it receives.
1> {ok, C} = prometheus_ranch_example_client:connect(tcp_echo, [binary]).
{ok, #Port<0.11>}
2> prometheus_ranch_example_client:send(C, <<"foo">>).
ok
3> prometheus_ranch_example_client:recv(C).
{ok, <<"foo">>}
4> prometheus_ranch_example_client:talk(C, <<"bar">>).
{ok, <<"bar">>}
5> prometheus_ranch_example_client:talk_random(C, 100).
{ok, <100 bytes of random data>}
6> prometheus_ranch_example_client:close(C).
ok