When do you begin to read a trilogy? When the first novel is published? Do you risk that the author — or the publisher — will lose interest, and that you will be left with an orphaned cliffhanger or an unrequited love? Or do you wait, and line up all three novels and devour them in turn? I recommend that you consider taking a middle course with “The Kingkiller Chronicle.” Start now! The first two books have been published, and Patrick Rothfuss, hounded by ardent fans, is hard at work on the third. Rothfuss does not write as fast as …