… error while USE_CUSTOM_TCP_CLIENT=on (#62)

cpp_redis::client client;

client.connect();

client.set("hello", "42");
client.get("hello", [](cpp_redis::reply& reply) {
  std::cout << reply << std::endl;
});
//! also support std::future
//! std::future<cpp_redis::reply> get_reply = client.get("hello");

client.sync_commit();
//! or client.commit(); for asynchronous call

cpp_redis::subscriber sub;

sub.connect();

sub.subscribe("some_chan", [](const std::string& chan, const std::string& msg) {
  std::cout << "MESSAGE " << chan << ": " << msg << std::endl;
});
sub.psubscribe("*", [](const std::string& chan, const std::string& msg) {
  std::cout << "PMESSAGE " << chan << ": " << msg << std::endl;
});

sub.commit();