[1.7.10] Reply messages (packets)

So I know that I can send reply, but what if I want to send few replies?

Just wanna know if using PacketHandler.dispatcher.send... //to someone

inside onMessage() of some of my message handler (receiver) is safe and won't cause some receive-packet lags (in case of huge code in onMessage())?

Client ---(sends one packet to server)---> Server (reads) ---(inside onMessage() creates 5 different packets and sends them somewhere)---> Clients that should receive packets.

Asking because, well - return message inside onMessage exists for some reason - but is it just wrapper (you have sender there and all stuff) that will simply send back message just like normal PacketHandler.dispatcher.send... or there is something more in that?

To be even more clear - is there an actual difference in those codes:

@Override
	public IMessage onMessage(...cut...)
	{
		//data is a NBTTag. Inside PacketReplyMessage it's being unpdacked analysed and send back to client.
		return new PacketReplyMessage((NBT)data);
	}

and

@Override
	public IMessage onMessage(...cut...)
	{
		//Shitload of getting and comparing from some string arrays, putting up data and then sending it in (String)data.
		//In previous example everything above happens inside new reply packet instead of here in onMessage().
		PacketHandler.dispatcher.sendTo(new PacketReplyMessage((String)data), player);
		return null;
	}