Bug report

I'm following the Quality of Service demos at https://github.com/ros2/demos/blob/master/quality_of_service_demo/README.md , and none of the liveliness demos seem to work for me.

Required Info:

• Operating System:
  • Ubuntu 18.04
• Installation type:
  • Source
• Version or commit hash:
  • cee4332
• DDS implementation:
  • Fast-RTPS
• Client library (if applicable):
  • rclcpp/rclpy

Steps to reproduce issue

ros2 run quality_of_service_demo_cpp liveliness 1000 --kill-publisher-after 2000

Expected behavior

After 2 seconds, the publisher is killed and the subscriber gets a callback which prints out some information about liveliness.

Actual behavior

After 2 seconds, the publisher seems to be killed (at least, it stops printing), but we get no information about liveliness.

Additional information

This is failing for both quality_of_service_demo_cpp and quality_of_service_demo_py. Further, trying to run ros2 run quality_of_service_demo_cpp liveliness 250 --node-assert-period 0 --policy MANUAL_BY_NODE throws an exception on startup saying "Manual liveliness unsupported for fastrtps", but that is not mentioned in the README. @emersonknapp FYI.