This method leaks internal info (ip/mac), and is not as collision resistant as the one I propose. imagine you have an embedded system that after a restart has t

This method leaks internal info (ip/mac), and is not as collision resistant as the one I propose. imagine you have an embedded system that after a restart has the internal clock reset because of clock battery failure. Pid and thread_id are the same after every restart (or may be the same) because of the OS initialization steps which are simple and deterministic. You have your system in "reboot loop" for some reason. It reboots every few minutes. Soon or later you'll generate a repeated ID. Given the method is also more complex, why to use it?