Scott picked up the leash and we walked out the door with Boomer like we had so many times before. Only this time we weren’t heading out to explore the city or to let Boomer stretch his legs. This time we were going to say goodbye. To him. Cancer. We’ve heard that diagnosis before – when medical tests found the cause of our 13-year-old son’s massive headache. This time the diagnosis was for our dog. We named him Boomer, a nod to Oklahoma, the place we raised our kids. The kids had begged and lobbied for another dog after Sundance. We told them to write a proposal detailing how this…