When this happens, it is incredibly noisy in the logs.
It accounts for about a third of all remaining
"unexpected" log lines from a recent investigation.
It's not clear that we know how to fix this,
we have a functioning workaround,
and we now have a (cheap and efficient) metric for this
that we can use for measurements.
So reduce the logging to approximately once per minute.
Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>
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