private static void writePacket(DataOutputStream os, long time, Packet packet) throws IOException {
        ByteBuf buf = PooledByteBufAllocator.DEFAULT.buffer();
        NetUtils.writeVarInt(buf, REVERSE_PACKET_MAP.get(packet.getClass()));
        packet.write(buf);
        int length = buf.readableBytes();

        os.writeInt((int) time);
        os.writeInt(length);
        buf.readBytes(os, length);
        buf.release();
    }