[tor-relays] Guard flag flapping

[starlight.2015q3 at binnacle.cx]

>I had already run tests with both speedtest-cli
>and iperf3. This server consistently achieves 200
>to 300 Mb/s in both directions, with both relays
>still running, and on some runs is hitting over
>800 Mb/s.

Final caveats:

If the server is on a shared gigabit link,
performance may not improve.  The difference
between a dedicated gigabit and a shared
gigabit is immense.  One expects an ISP
to load a shared GB links as heavily
as possible--I.E. up to the point
where customers complain and terminate
service.  True dedicated gigabit links
are expensive.

If it's running in a VPS that's showing
a gigabit link speed, the number is fiction.