def for(queue:, worker: nil)
      worker_name = worker.to_s.underscore.tr("/", "_") if worker
      [namespace, queue, worker_name].compact.join(".")
    end
def for(queue:, worker: nil)
      worker_name = worker.to_s.underscore.tr("/", "_") if worker
      [namespace, queue, worker_name].compact.join(".")
    end
Generates a metric name

 @param [String] queue
 @param [Class]  worker

 returns a String object