The process produces consciousness. They are simultaneous.
But obviously the process that is producing consciousness is only one of many processes going on.
As far as Libet, if you care, here's a philosophical examination of the experiment.
http://tap.sagepub.com/content/early/2012/10/15/0959354312460926.full.pdf+html
From our analyses in this article, we may conclude that the results of Libet’s study and
more recent Libet-type experiments do not permit strong (in particular, causal) claims
about the relation between neurological processes, conscious free will, and motor activity.
Instead, these experiments are better characterized as “exploratory experiments” (cf.
Steinle, 1997), which help to chart a developing area of intriguing neuroscientific research.
We are claiming, therefore, not that the experiments do not contribute at all to the debate
on neuroscience and free will, but rather that at present this contribution is still explora-
tory instead of providing a convincing test for or against the existence of free will.
So would you say that there is a difference between me and a zombie twin of me that does everything exactly as I do?
There is no such thing as a zombie twin.
Another empty rat hole to crawl into.
There is nothing to be gained in understanding of consciousness by pursuing imaginary nonentities.
But maybe I'm wrong.
What purpose is served in looking at imaginary "zombies"?
Especially when you have a very well written, although not so easily understood because it is complicated philosophical examination of the Libet experiments and the erroneous conclusions that seem to have become religious dogma in some circles.
The fields of cognitive science and AI have turned out so far to be major disappointments. Riddled with absolute rubbish and attempts to pass off preliminary research as the final word.