2.0.10 uses Netty 4's default ByteBuf allocator. In Netty 4.0.x, this is the unpooled variant, we want to use the pooled one instead.
Workaround: pass the VM option -Dio.netty.allocator.type=pooled.
Verified via profiling that PooledByteBufAllocator is now used given using the Default NettyOptions.