def track_deferrable(name, deferrable)
      attach_time = Time.now
      deferrable.callback do |*a|
        push_deferrable_values("#{name}_success", attach_time)
      end
      deferrable.errback do |*a|
        push_deferrable_values("#{name}_error", attach_time)
      end
    end
def track_deferrable(name, deferrable)
      attach_time = Time.now
      deferrable.callback do |*a|
        push_deferrable_values("#{name}_success", attach_time)
      end
      deferrable.errback do |*a|
        push_deferrable_values("#{name}_error", attach_time)
      end
    end
Attaches additional callback and errback to deferrable to track
 a common set of success/error rate/latency