Bridge project update (Week of April 21st)

Hi,

This is likely the last update.

The main change (and the final test case) has been committed: 
https://svnweb.freebsd.org/changeset/base/360345
(And https://svnweb.freebsd.org/changeset/base/360346)

I intend to MFC this to stable/12 in due course, but it will do no hard 
to let it get a bit more testing in CURRENT first.

The Foundation wrote about this project here: 
https://www.freebsdfoundation.org/blog/500-if_bridge-performance-improvement/
There will be an in-depth article on this work in the upcoming May/June 
issue of FreeBSD Journal.

Best regards,
Kristof Provost