Use PulsarByteBufAllocator to allocate buffer for chunks at consumer …

…side (apache#13536)

### Motivation

Currently Pulsar consumer allocates memory from direct memory via `Unpooled.directBuffer` directly, which doesn't make use of the widely used allocator in Pulsar.

### Modifications

Use `PulsarByteBufAllocator` as the memory allocator for chunks buffer.

pulsar-client/src/main/java/org/apache/pulsar/client/impl/ConsumerImpl.java

@@ -26,7 +26,6 @@
 import com.scurrilous.circe.checksum.Crc32cIntChecksum;
 
 import io.netty.buffer.ByteBuf;
-import io.netty.buffer.Unpooled;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.util.Recycler;
 import io.netty.util.Recycler.Handle;
@@ -1270,7 +1269,7 @@ private ByteBuf processMessageChunk(ByteBuf compressedPayload, MessageMetadata m
         }
 
         if (msgMetadata.getChunkId() == 0) {
-            ByteBuf chunkedMsgBuffer = Unpooled.directBuffer(msgMetadata.getTotalChunkMsgSize(),
+            ByteBuf chunkedMsgBuffer = PulsarByteBufAllocator.DEFAULT.buffer(msgMetadata.getTotalChunkMsgSize(),
                     msgMetadata.getTotalChunkMsgSize());
             int totalChunks = msgMetadata.getNumChunksFromMsg();
             chunkedMessagesMap.computeIfAbsent(msgMetadata.getUuid(),