Updates #11058 Change-Id: I35e7ef9b90e83cac04ca93fd964ad00ed5b48430 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
From Go commit 0a48e5cbfabd679e, then with some generics sprinkled about. Updates tailscale/corp#7354 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>