notifyOutgoingListeners(packet) {
        if (this._anyOutgoingListeners && this._anyOutgoingListeners.length) {
            const listeners = this._anyOutgoingListeners.slice();
            for (const listener of listeners) {
                listener.apply(this, packet.data);
            }
        }
    }
Notify the listeners for each packet sent

@param packet

@private