Don't use ByteBuf, fix varint with 0 ending

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

@@ -2,11 +2,9 @@ package com.velocitypowered.proxy.protocol.netty;
 
 import com.velocitypowered.proxy.protocol.ProtocolUtils;
 import io.netty.buffer.ByteBuf;
-import io.netty.buffer.Unpooled;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.ByteToMessageDecoder;
 import io.netty.handler.codec.CorruptedFrameException;
-import java.util.Arrays;
 import java.util.List;
 
 public class MinecraftVarintFrameDecoder extends ByteToMessageDecoder {
@@ -17,38 +15,32 @@ public class MinecraftVarintFrameDecoder extends ByteToMessageDecoder {
       return;
     }
 
-    ByteBuf lenBuf = ctx.alloc().buffer(3).writeZero(3);
     int origReaderIndex = in.readerIndex();
-    try {
-      for (int i = 0; i < 3; i++) {
-        if (!in.isReadable()) {
+    for (int i = 0; i < 3; i++) {
+      if (!in.isReadable()) {
+        in.readerIndex(origReaderIndex);
+        return;
+      }
+
+      byte read = in.readByte();
+      if (read >= 0) {
+        // Make sure reader index of length buffer is returned to the beginning
+        in.readerIndex(origReaderIndex);
+        int packetLength = ProtocolUtils.readVarInt(in);
+        if (packetLength == 0) {
+          return;
+        }
+
+        if (in.readableBytes() < packetLength) {
           in.readerIndex(origReaderIndex);
           return;
         }
 
-        byte read = in.readByte();
-        lenBuf.setByte(i, read);
-        if (read > 0) {
-          // Make sure reader index of length buffer is returned to the beginning
-          lenBuf.readerIndex(0);
-          int packetLength = ProtocolUtils.readVarInt(lenBuf);
-          if (packetLength == 0) {
-            return;
-          }
-
-          if (in.readableBytes() < packetLength) {
-            in.readerIndex(origReaderIndex);
-            return;
-          }
-
-          out.add(in.readRetainedSlice(packetLength));
-          return;
-        }
+        out.add(in.readRetainedSlice(packetLength));
+        return;
       }
-
-      throw new CorruptedFrameException("VarInt too big");
-    } finally {
-      lenBuf.release();
     }
+
+    throw new CorruptedFrameException("VarInt too big");
   }
 }