This updates all source files to use a new standard header for copyright
and license declaration. Notably, copyright no longer includes a date,
and we now use the standard SPDX-License-Identifier header.
This commit was done almost entirely mechanically with perl, and then
some minimal manual fixes.
Updates #6865
Signed-off-by: Will Norris <will@tailscale.com>
Map is a concurrent safe map that is a trivial wrapper
over a Go map and a sync.RWMutex.
It is optimized for use-cases where the entries change often,
which is the opposite use-case of what sync.Map is optimized for.
The API is patterned off of sync.Map, but made generic.
Signed-off-by: Joe Tsai <joetsai@digital-static.net>
