Hack to work around xml2rfcv2 bugs:

a code block with "language" tbreak will make newlines and leading spaces significant, but not turn into a figure.
(Think nroff .nf, if you are old enough :-)

~~~ tbreak
line 1
line 2
  line 3
~~~

will come out mostly unchanged in the .TXT.  Still needs a couple of fixes for the HTML, upcoming.