client() -> {ok, Sock} = gen_tcp:connect("localhost", 5678, [binary, {packet, 0}]), ok = gen_tcp:send(Sock, "Some Data"), ok = gen_tcp:close(Sock).

server() -> {ok, LSock} = gen_tcp:listen(5678, [binary, {packet, 0}, {active, false}]), {ok, Sock} = gen_tcp:accept(LSock), {ok, Bin} = do_recv(Sock, []), ok = gen_tcp:close(Sock), ok = gen_tcp:close(LSock), Bin.
do_recv(Sock, Bs) -> case gen_tcp:recv(Sock, 0) of {ok, B} -> do_recv(Sock, [Bs, B]); {error, closed} -> {ok, list_to_binary(Bs)} end.