I noticed we were allocating these every time when they could just
share the same memory. Rather than document ownership, just lock it
down with a view.
I was considering doing all of the fields but decided to just do this
one first as test to see how infectious it became. Conclusion: not
very.
Updates #cleanup (while working towards tailscale/corp#20514)
Change-Id: I8ce08519de0c9a53f20292adfbecd970fe362de0
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
bd93c3067e