Meanwhile, in another medium saucepan heat the remaining 2 teaspoons olive oil over medium heat. Add corn and onion; cook 6 to 8 minutes or until corn is tender and onion is lightly browned. Add rice, mushrooms, and the remaining 2 cloves garlic; cook and stir about 5 minutes or until rice is golden brown, stirring frequently. Carefully add 1/2 cup of the broth mixture, stirring to loosen brown bits from bottom of saucepan. Bring to boiling; reduce heat. Simmer, uncovered, 3 to 4 minutes or until the rice has absorbed the liquid.