title: ROS2: publish last message on sigint(ctrl+c)
body: <p>Is it possible to send one last message on shutdown using ros2?
  The problem here is that rclcpp::shutdown is always called first, so no message can be send in the destructor of the node.</p>
  <p>Using rclcpp::on_shutdown() also not work as rclcpp is sigint first. here i get the error always when logging as well: Failed to publish log message to rosout: publisher's context is invalid, at /tmp/binarydeb/ros-galactic-rcl-3.1.3/src/rcl/publisher.c:352</p>
  <p>when just publishing i get an exception error.</p>