Resultive conjunct or clause of result

Hi everybody! I have a final exam tomorrow and I have this little doubt which is disturbing me.

My sentence says: 'He read the book carefully, so he acquired a good knowledge".

Should I say that 'so' is a resultive conjunct (and therefore leave it outside the predicate)?
Or should I say that 'so' is a subordinating conjunction for the second part of the sentence is an adverbial adjunct or result?

Thanks in advance! And I'll take the opporunity to say that I really admire some people over here! You DO know!

Look forward to your replies!