time.Since has optimizations for measuring monotonic time.
For #31160.
Change-Id: I0529b9f69b9f008e3414b8e386b6faa64af4a008
Reviewed-on: https://go-review.googlesource.com/c/go/+/582135
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org> Reviewed-by: Cherry Mui <cherryyz@google.com> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>