The current version on rubygems.org is 0.10.8, but the docs on http://ruby-prof.rubyforge.org are for version 0.7 or
so. This is unfortunate since the README example passes an int instead of a hash to printer.print, which now causes
an error:

ruby-prof/abstract_printer.rb:26:in `[]': can't convert Symbol into Integer (TypeError)

See also https://gist.github.com/987528