code: private EmbeddedChannel newCompressionChannel(final ChannelHandlerContext ctx, ZlibWrapper wrapper) {
          return new EmbeddedChannel(ctx.channel().id(), ctx.channel().metadata().hasDisconnect(),
                  ctx.channel().config(), ZlibCodecFactory.newZlibEncoder(wrapper, compressionLevel, windowBits,
                  memLevel));
      }
docs: Generate a new instance of an {@link EmbeddedChannel} capable of compressing data
  @param ctx the context.
  @param wrapper Defines what type of encoder should be used