This commit adds a new usermetric package and wires
up metrics across the tailscale client.
Updates tailscale/corp#22075
Co-authored-by: Anton Tolchanov <anton@tailscale.com>
Signed-off-by: Kristoffer Dalby <kristoffer@tailscale.com>
And make NewMultiLabelMap panic earlier (at construction time)
if the comparable struct type T violates the documented rules,
rather than panicking at Add time.
Updates #cleanup
Change-Id: Ib1a03babdd501b8d699c4f18b1097a56c916c6d5
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
