Clean, wash, and dry the rabbit. Melt the butter in a Dutch oven. Brown the rabbit in it. Sprinkle with the salt (optional), pepper, and flour, stirring until the flour browns. Add the broth and wine; bring to a boil, cover and cook over low heat 45 minutes to one hour or until tender. While the rabbit is cooking, brown the bacon lightly in a skillet; pour off half the fat. Add the onions; saute until golden. Add the garlic and mushrooms; saute 3 minutes. Add this mixture to the rabbit; cook 15 minutes longer or until the rabbit is tender. Note: If mixture seems dry, you can add a little more beef broth or wine to the mixture while it is cooking.