ao2_callback() is a much more efficient way of performing an operation on every
item in the container. This change makes hashtest2 run in about 25% of the
time it ran before on my system.
In general, I would say that it makes the most sense to use an ao2_iterator if
the operation being performed is going to take a long time and you don't want
to keep the container locked while you work with each object. Otherwise,
the use of ao2_callback is preferred.
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@82282 65c4cc65-6c06-0410-ace0-fbb531ad65f3
