Qi Wang 837b37c4ce Fix the time-since computation in HPA.
nstime module guarantees monotonic clock update within a single nstime_t.  This
means, if two separate nstime_t variables are read and updated separately,
nstime_subtract between them may result in underflow.  Fixed by switching to the
time since utility provided by nstime.
2021-12-21 23:37:22 -08:00
..
2021-06-24 07:40:28 -07:00