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>
Periodically poll the TCP RTT metric from all open TCP connections and
update a (bucketed) histogram metric.
Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: I6214902196b05bf7829c9d0ea501ce0e13d984cf