MAP_CHUNKのpacketを改変して、Y-61にある草ブロックを石にしたい

import:
    ch.njol.skript.Skript

    org.bukkit.Bukkit
    org.bukkit.plugin.Plugin

    com.comphenix.protocol.events.PacketListener
    com.comphenix.protocol.events.ListeningWhitelist
    com.comphenix.protocol.events.ListenerPriority
    com.comphenix.protocol.events.ListenerOptions
    com.comphenix.protocol.events.PacketAdapter
    com.comphenix.protocol.events.PacketEvent
    com.comphenix.protocol.events.PacketContainer
    com.comphenix.protocol.ProtocolLibrary
    com.comphenix.protocol.PacketType
    com.comphenix.protocol.injector.GamePhase
    com.comphenix.protocol.reflect.StructureModifier

    java.lang.Override
    java.util.ArrayList
    java.lang.System

preimport:
  jp.nlaocs.BlockPackets

public class BlockPackets extends PacketAdapter:

    public BlockPackets():
        super[Plugin, ListenerPriority, PacketType[]](Skript.getInstance(), ListenerPriority.NORMAL, [PacketType.Play.Server.MAP_CHUNK as PacketType])
    
    @Override
    public void onPacketSending(PacketEvent event):

        set {_packet} to {_event}.getPacket()

        broadcast "&aPacket: %{_packet}%"

on load:
    set {blockpacketlistener} to new BlockPackets()
    ProtocolLibrary.getProtocolManager().addPacketListener({blockpacketlistener})

on unload:
    ProtocolLibrary.getProtocolManager().removePacketListener({blockpacketlistener})
    clear {blockpacketlistener}