I need to be able to send simple "Cookie:" header with Net::HTTP request

Documentation I've been able to find is very unspecific about headers, which are
apparently handled under the HTTP::Header class, right?

I'd like to be able to add any arbitrary HTTP header to my requests I am making
with Net::HTTP.get_response, but I cannot seem to make this work. There seem to be a
complete set of methods here. Can someone point out to me how they work? Or even
better a document that illustrates how to do these outgoing headers?

I basically need these in a test environment, and I need to send out a cookie that
the SUT is presumed to have sent.

Sincerely, Xeno