Images plugin throws NoSuchElementException: packet_handler on Paper 1.21.10

[Hurming]

Description

When a player joins the server, the Images plugin throws a NoSuchElementException related to Netty's channel pipeline.

The error happens during player join, when the plugin attempts to inject a packet listener.

Error / Stacktrace

[07:58:03 WARN]: [Images] Task #271889 for Images v2.5.8 generated an exception
java.util.NoSuchElementException: packet_handler
        at io.netty.channel.DefaultChannelPipeline.getContextOrDie(DefaultChannelPipeline.java:1022) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
        at io.netty.channel.DefaultChannelPipeline.internalAdd(DefaultChannelPipeline.java:179) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
        at io.netty.channel.DefaultChannelPipeline.addBefore(DefaultChannelPipeline.java:246) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
        at io.netty.channel.DefaultChannelPipeline.addBefore(DefaultChannelPipeline.java:240) ~[netty-transport-4.1.118.Final.jar:4.1.118.Final]
        at images-2.5.8.jar/com.andavin.images.v1_21_R6.PacketListener.setEntityListener(PacketListener.java:82) ~[images-2.5.8.jar:?]
        at images-2.5.8.jar/com.andavin.images.Images.lambda$onJoin$6(Images.java:201) ~[images-2.5.8.jar:?]
        at org.bukkit.craftbukkit.scheduler.CraftTask.run(CraftTask.java:78) ~[paper-1.21.10.jar:1.21.10-129-3e25649]
        at org.bukkit.craftbukkit.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:474) ~[paper-1.21.10.jar:1.21.10-129-3e25649]
        at net.minecraft.server.MinecraftServer.tickChildren(MinecraftServer.java:1744) ~[paper-1.21.10.jar:1.21.10-129-3e25649]
        at net.minecraft.server.MinecraftServer.tickServer(MinecraftServer.java:1618) ~[paper-1.21.10.jar:1.21.10-129-3e25649]
        at net.minecraft.server.dedicated.DedicatedServer.tickServer(DedicatedServer.java:430) ~[paper-1.21.10.jar:1.21.10-129-3e25649]
        at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1338) ~[paper-1.21.10.jar:1.21.10-129-3e25649]
        at net.minecraft.server.MinecraftServer.lambda$spin$2(MinecraftServer.java:384) ~[paper-1.21.10.jar:1.21.10-129-3e25649]
        at java.base/java.lang.Thread.run(Thread.java:1583) ~[?:?]

Environment

• Server software: Paper
• Server version: 1.21.10
• Images version: 2.5.8
• Java version: Java 21

Expected behavior

The player should be able to join without any errors, and the Images plugin should inject its packet listener successfully.

Actual behavior

An exception is thrown on player join, indicating that the packet_handler does not exist in the Netty channel pipeline.

Additional notes

It seems that the plugin is trying to add a handler before packet_handler, which may no longer exist or has been renamed in newer Paper / Minecraft versions (1.21.10 / v1_21_R6).