retrooper/packetevents — reverse-engineered prompt

Build me a Java library for Minecraft Java Edition that makes packet handling much easier for plugin and mod developers. I want a clean API where people can listen to incoming and outgoing packets, read and change packet data, cancel packets when needed, and send packets manually without dealing with the messy low level protocol details every time.

It should feel usable across the main Minecraft server ecosystems, especially Spigot, BungeeCord, Velocity, Sponge, and Fabric, with shared core logic and platform specific hooks where needed. Include packet wrapper style classes or helpers so common packet types are easier to work with than raw network buffers. It should be set up as a real reusable library, not just a demo, with sensible docs or examples showing how to register listeners and send packets.

Please make it production ready and organized enough that other developers could actually depend on it. If anything is unclear, look up the current Minecraft packet and platform docs online and follow the existing project style.