Simplify the discard logic.

proxy/src/main/java/com/velocitypowered/proxy/connection/MinecraftConnection.java

@@ -16,7 +16,6 @@ import com.velocitypowered.natives.encryption.VelocityCipher;
 import com.velocitypowered.natives.encryption.VelocityCipherFactory;
 import com.velocitypowered.natives.util.Natives;
 import com.velocitypowered.proxy.VelocityServer;
-import com.velocitypowered.proxy.network.netty.DiscardHandler;
 import com.velocitypowered.proxy.protocol.MinecraftPacket;
 import com.velocitypowered.proxy.protocol.StateRegistry;
 import com.velocitypowered.proxy.protocol.netty.MinecraftCipherDecoder;
@@ -152,7 +151,6 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
         }
       }
 
-      installDiscardHandler(ctx);
       ctx.close();
     }
   }
@@ -168,18 +166,6 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
     Preconditions.checkState(this.channel.eventLoop().inEventLoop(), "Not in event loop");
   }
 
-  private void installDiscardHandler(ChannelHandlerContext ctx) {
-    if (ctx.pipeline().get("discard") == null) {
-      ctx.pipeline().addBefore(MINECRAFT_DECODER, "discard", DiscardHandler.HANDLER);
-    }
-  }
-
-  private void installDiscardHandler() {
-    if (channel.pipeline().get("discard") == null) {
-      channel.pipeline().addBefore(MINECRAFT_DECODER, "discard", DiscardHandler.HANDLER);
-    }
-  }
-
   public EventLoop eventLoop() {
     return channel.eventLoop();
   }
@@ -220,7 +206,6 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
   public void closeWith(Object msg) {
     if (channel.isActive()) {
       knownDisconnect = true;
-      installDiscardHandler();
       channel.writeAndFlush(msg).addListener(ChannelFutureListener.CLOSE);
     }
   }
@@ -230,7 +215,6 @@ public class MinecraftConnection extends ChannelInboundHandlerAdapter {
    */
   public void close() {
     if (channel.isActive()) {
-      installDiscardHandler();
       channel.close();
     }
   }

proxy/src/main/java/com/velocitypowered/proxy/network/netty/DiscardHandler.java

@@ -1,17 +0,0 @@
-package com.velocitypowered.proxy.network.netty;
-
-import io.netty.channel.ChannelHandler.Sharable;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.ChannelInboundHandlerAdapter;
-import io.netty.util.ReferenceCountUtil;
-
-@Sharable
-public class DiscardHandler extends ChannelInboundHandlerAdapter {
-
-  public static final DiscardHandler HANDLER = new DiscardHandler();
-
-  @Override
-  public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
-    ReferenceCountUtil.release(msg);
-  }
-}

proxy/src/main/java/com/velocitypowered/proxy/protocol/netty/MinecraftVarintFrameDecoder.java

@@ -14,6 +14,11 @@ public class MinecraftVarintFrameDecoder extends ByteToMessageDecoder {
 
   @Override
   protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) {
+    if (!ctx.channel().isActive()) {
+      in.skipBytes(in.readableBytes());
+      return;
+    }
+
     while (in.isReadable()) {
       int varintEnd = in.forEachByte(reader);
       if (varintEnd == -1) {