Main.java

public class Main extends JavaPlugin {
    private static final boolean ASYNC = true;
 
    public void onEnable() {
        AsyncListenerHandler handler = ProtocolLibrary.getProtocolManager().getAsynchronousManager().registerAsyncHandler(new PacketAdapter(this, PacketType.Play.Server.RESPAWN) {
            public void onPacketSending(PacketEvent event) {
                getLogger().info("Sending respawn packet to " + event.getPlayer().getName());
            }
        });
 
        if (ASYNC) {
            handler.start();
        } else {
            handler.syncStart();
        }
    }
 
    public boolean onCommand(CommandSender sender, Command command, String label, String[] args) {
        Player player = (Player) sender;
        player.setHealth(0);
        player.spigot().respawn();
    }
}