Preheat oven to 375 (basically following directions on back of crescent roll package). Brown chicken, onion and mushrooms together over medium heat. Remove from heat when cooked through and stir in 8 oz. pkg. cream cheese until melted. Open crescent rolls, and pinch seams of two triangles per piece together. You will get 4 squares out of each can of dough - recipe will make approx. 8 squares will some filling left over. Put chicken mixture on one side of square and fold over to seal dough. If you prefer, you can use some egg white to seal the top of the square and sprinkle breadcrumbs over it as well. Bake in over for 11 - 13 minutes, or until lightly browned.