I wouldnt say anything to the dog or make eye contact really. I would stand up tall and straight and remain relaxed and calm and stare off into the distance. If the dog wants to eat me there isnt much i am going to be able to do but try and avoid the situation. Once the dog got to my personal space, i would walk away non-threateningly and at a normal pace. Ive had to do this before... i think the best thing is remaining calm and not acting like a threat to the dog, but also not acting weak either.