The enqueuedAt field exists only to compute an elapsed duration for the
average queue duration metric, so it doesn't need a wall clock reading.
A time.Time is 24 bytes and contains a pointer (its *Location), which
the GC has to scan in every queued pkt. A mono.Time is 8 bytes of plain
integer, shrinking pkt from 80 to 64 bytes, which matters a little now
and more in a following commit that keeps pkt ring buffers in a pool.
mono.Now is also cheaper than the clock interface's Now on Linux.
Updates #21064
Change-Id: I9c4e2a71d5b8f3062e94a8c7b1d3f5e60a2c4b8d
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Brad Fitzpatrick
6a57eaf403