def uptime
      send_message!(Protocol::Device::GetInfo.new,
         wait_for: Protocol::Device::StateInfo) do |payload|
        payload.uptime.to_f / NSEC_IN_SEC
      end
    end
def uptime
      send_message!(Protocol::Device::GetInfo.new,
         wait_for: Protocol::Device::StateInfo) do |payload|
        payload.uptime.to_f / NSEC_IN_SEC
      end
    end
Return device uptime
 @api private
 @return [Float] Device uptime in seconds