Fix Varint21FrameDecoder cached length buf usage

patches/server/0450-Optimize-NetworkManager-Exception-Handling.patch

@@ -17,10 +17,10 @@ index 672e296cec289abd3bf797d84e16983ca50907be..aec921477e035095d569eab3335175b9
              return function != null ? function.apply(buf) : null;
          }
 diff --git a/src/main/java/net/minecraft/network/Varint21FrameDecoder.java b/src/main/java/net/minecraft/network/Varint21FrameDecoder.java
-index 99b581052f937b0f2d6b5d73de699008c1d51774..ed54479b14dcfc736ac90749106557f0ff537550 100644
+index 99b581052f937b0f2d6b5d73de699008c1d51774..81ec2011a93bb94200ad750f4666ba1cd8be11c5 100644
 --- a/src/main/java/net/minecraft/network/Varint21FrameDecoder.java
 +++ b/src/main/java/net/minecraft/network/Varint21FrameDecoder.java
-@@ -8,8 +8,20 @@ import io.netty.handler.codec.CorruptedFrameException;
+@@ -8,9 +8,20 @@ import io.netty.handler.codec.CorruptedFrameException;
  import java.util.List;
  
  public class Varint21FrameDecoder extends ByteToMessageDecoder {
@@ -34,13 +34,14 @@ index 99b581052f937b0f2d6b5d73de699008c1d51774..ed54479b14dcfc736ac90749106557f0
 +        }
 +        // Paper end
          byteBuf.markReaderIndex();
+-        byte[] bs = new byte[3];
 +        // Paper start - reuse temporary length buffer
-+        byte[] abyte = lenBuf;
-+        java.util.Arrays.fill(abyte, (byte) 0);
++        byte[] bs = lenBuf;
++        java.util.Arrays.fill(bs, (byte) 0);
 +        // Paper end
-         byte[] bs = new byte[3];
  
          for(int i = 0; i < bs.length; ++i) {
+             if (!byteBuf.isReadable()) {
 diff --git a/src/main/java/net/minecraft/network/protocol/PacketUtils.java b/src/main/java/net/minecraft/network/protocol/PacketUtils.java
 index 049e64c355d5f064009b1107ad15d28c44f999dd..acfa1907bfc9c29d261cfccc00d65bad9ad1a002 100644
 --- a/src/main/java/net/minecraft/network/protocol/PacketUtils.java