fix: Const correctness

src/net/tcp_server_socket.cpp

@@ -87,7 +87,7 @@ void tcp_server_socket::await_raw_socket_incomming(async_server_socket::self_ptr
 	this->client_listener(tcp_client(std::bind(&tcp_server_socket::client_destructed_cb, this, _1), auto_fd(client_fd_raw), address, port));
 }
 
-int tcp_server_socket::get_number_of_connected_clients() {
+int tcp_server_socket::get_number_of_connected_clients() const {
 	return this->number_of_connected_clients;
 }
 

src/net/tcp_server_socket.hpp

@@ -25,7 +25,7 @@ private:
 	int number_of_connected_clients;
 public:
 	tcp_server_socket(uint16_t port, incoming_client_listener_type client_listener_);
-	int get_number_of_connected_clients();
+	int get_number_of_connected_clients() const;
 private:
 	void await_raw_socket_incomming(async_server_socket::self_ptr_type ass, const auto_fd& socket);
 	void client_destructed_cb(tcp_client::exit_status exit_status);