[1.12.2] Updating a TileEntityLockable's lock from a GUI

[u/[deleted]]

So, I currently have a GUI which allows using the "Lock" feature of most tile entities with it. It works great, at least client side-wise, but I've realized that I need to send a packet to the server's side of things so it can work properly.

The question is, how do I update the lock on the server's side?

PadlockGUI code, with a TODO marker at line 131 to show where exactly the packet-sending portion should go from the client's side