Potential Multi-Threading Candidates in ROS2

Dear ROS Community,

I am working on the topic of understanding how multi-threading can influence the execution time of particular functions and algorithms. In order to conduct tests and benchmarks, I need functions and algorithms that could potentially benefit from multi-threading. Concretely, I am asking for any of these points:

  1. Any open source project that could benefit from multi-threading (your personal project, or any other project stack)
  2. Any known function that is used commonly often in ROS and could benefit from multi-threading.
  3. Functions or algorithms containing loops with many iterations.

Thank you in advance.