In a red plastic basket, oval-shaped and lined with crinkly paper, a pillow-soft bun arrives with one expertly charred hot dog layered with oozy chili (the kind made for topping, like gravy), bright Eastern Carolina slaw (the white kind, not the red), diced white onions, and a switchback squiggle of yellow mustard. Or, spoken like a Carolinian: mustard, slaw, chili, ’n’ onions.