code: public static void recycle(@NotNull ByteBuf buf) {
  		int slab = 32 - numberOfLeadingZeros(buf.array.length - 1);
  		ByteBufConcurrentStack stack = slabs[slab];
  		stack.push(buf);
  	}
docs: Returns provided ByteBuf to the ByteBufPool to the appropriate slab.
  
  @param buf the ByteBuf to be recycled