Cleaner and more correct to use ByteBufs directly.

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

@@ -11,41 +11,42 @@ import java.util.List;
 
 public class MinecraftVarintFrameDecoder extends ByteToMessageDecoder {
 
-  private final byte[] lenBuf = new byte[3];
-
   @Override
   protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
     if (!in.isReadable()) {
       return;
     }
 
-    Arrays.fill(lenBuf, (byte) 0);
+    ByteBuf lenBuf = ctx.alloc().buffer(3);
     int origReaderIndex = in.readerIndex();
-
-    ByteBuf wrappedBuf = Unpooled.wrappedBuffer(lenBuf);
-    for (int i = 0; i < lenBuf.length; i++) {
-      if (!in.isReadable()) {
-        in.readerIndex(origReaderIndex);
-        return;
-      }
-
-      lenBuf[i] = in.readByte();
-      if (lenBuf[i] > 0) {
-        int packetLength = ProtocolUtils.readVarInt(wrappedBuf);
-        if (packetLength == 0) {
-          return;
-        }
-
-        if (in.readableBytes() < packetLength) {
+    try {
+      for (int i = 0; i < 3; i++) {
+        if (!in.isReadable()) {
           in.readerIndex(origReaderIndex);
           return;
         }
 
-        out.add(in.readRetainedSlice(packetLength));
-        return;
-      }
-    }
+        byte read = in.readByte();
+        lenBuf.writeByte(read);
+        if (read > 0) {
+          int packetLength = ProtocolUtils.readVarInt(lenBuf.slice());
+          if (packetLength == 0) {
+            return;
+          }
 
-    throw new CorruptedFrameException("VarInt too big");
+          if (in.readableBytes() < packetLength) {
+            in.readerIndex(origReaderIndex);
+            return;
+          }
+
+          out.add(in.readRetainedSlice(packetLength));
+          return;
+        }
+      }
+
+      throw new CorruptedFrameException("VarInt too big");
+    } finally {
+      lenBuf.release();
+    }
   }
 }