Modify packet before it's sent

I need to modify a packet before it’s sent (namely, I need to change the UUID of a LoginSuccessPacket). Since I’m using PacketLib, I have no control over what UUID is used during the sending of said packet, and would like to change it after session#send has been called, but before it’s actually sent. Is there a way I can do this, or no? Thanks!

[Steveice10]

Yes, but as I keep saying, why do you need to modify packets to accomplish this when you can just disable authentication and give it whatever username you want to begin with?

My point is, if you are using authentication, modifying packets won’t work because it will be invalid, and if you aren’t, you can just use any username you want anyway.

[DaMatrix]

I’ve fixed it by making my own class with the same canocial name as the class of the packet I was trying to modify, just tweaking a copypaste of the original code. But there should be a way to do this less hackily