Add a TODO which should be done when buffer pool is implemented

transport/src/main/java/io/netty/channel/DefaultChannelPipeline.java

@@ -1468,6 +1468,7 @@ public class DefaultChannelPipeline implements ChannelPipeline {
         public ChannelBuf newOutboundBuffer(ChannelHandlerContext ctx) throws Exception {
             switch (channel.metadata().bufferType()) {
             case BYTE:
+                // TODO: Use a direct buffer once buffer pooling is implemented.
                 return Unpooled.buffer();
             case MESSAGE:
                 return Unpooled.messageBuffer();