pub fn process_started_at(pid: u32) -> Option<String>Expand description
An opaque marker identifying which process currently holds pid, not
merely whether the number is in use — the OS-reported moment it started.
Compared only for equality by the caller, never parsed as a timestamp:
the two platform formats are not on the same scale, and nothing here
needs to be.
A live pid alone never proves it is the process a caller thinks it is —
pids get reused, sometimes within minutes on a busy machine — so
crate::run::RunState::liveness uses this to corroborate a driver_pid
that answered pid_status(..) == Some(true): it records this marker
alongside the pid, and a later mismatch means a different process now
answers to that number, not that the original one is somehow still
running under it. None when the platform could not say — a caller must
treat that exactly like an unavailable pid_status query, not as
either a match or a mismatch.