Header folding

It appears that the read method in Mail::Message::Construct::Read assumes
that all header lines are already folded and makes no effort to fold them.
Is there any (easy) way around this in the case that the header has lines
that are, in fact, not folded?

I have the entire message in a scalar variable and would like to use read to
put it into a Mail::Message object.  From there, I need to evaluate and
sometimes modify header information (to do spam marking, etc) before
inserting the message into a database for a database-driven mail system.