Late last month, off Beach 108th Street in New York City’s Rockaway Beach, the New York City Fire Department’s Robotics Unit helped rescue a distressed swimmer by doing something that would have sounded like science fiction not too long ago: sending flying robots over the surf to deliver flotation devices while lifeguards battled their way out to the victim. And it wasn’t a one-off: It was the second such rescue along Rockaway Beach this summer. In June, the Robotics Unit deployed drones to help two swimmers in trouble. Then, in July, another swimmer found himself at the mercy of the rip and swell. Once again, the robots went to work. The playbook is becoming pretty compelling: Find the swimmer from above. Get something buoyant and fluorescent to them immediately. Keep eyes on the victim. Then let the human beings, the people who actually have to get in the water, finish the job.…