get port() {
        // Initialize port if it does not exist yet
        // Ensure there is a listening socket before returning port
        if (this.#port === undefined) {
            // Throw error if listening socket does not exist
            if (!this.#listen_socket)
                throw new Error(
                    'HyperExpress: Server.port is not available as the server is not listening. Please ensure you called already Server.listen() OR have not yet called Server.close() when accessing this property.'
                );

            // Cache the resolved port
            this.#port = uWebSockets.us_socket_local_port(this.#listen_socket);
        }

        // Return port
        return this.#port;
    }
Returns the local server listening port of the server instance.
@returns {Number}