TimersManager doesn't follow ROS time

[alsora]

Feature request

Feature description

Currently, the TimersManager class waits for timers to be ready using the following code

timers_cv_.wait_for(lock, time_to_sleep.value(), [this]() {return timers_updated_;});

This will always sleep using the system clock, even if the "time to sleep" was computed from a timer using the ROS clock

We should take into account the clock type when deciding how to sleep, and use an API that is aware of ROS clock

[fujitatomoya]

duplication of #2457. lets keep this alive as tracking issue, and i will close #2457.
CC: @alsora

[alsora]

Ops, my bad.
I started looking into this problem and created a ticket without noticing we already had one.

[ros-discourse]

This issue has been mentioned on ROS Discourse. There might be relevant details there:

https://discourse.ros.org/t/the-ros-2-c-executors/38296/4

[ros-discourse]

This issue has been mentioned on ROS Discourse. There might be relevant details there:

https://discourse.ros.org/t/the-ros-2-c-executors/38296/13