To test the performance of the importer plugin I enabled Xdebug which is included in Vagrant's install of PHP. All you have to do to enable it is add the following lines to the php.ini file. Which is either etc/php/5.6/cli/php.ini
for command line or etc/php/5.6/fpm
for nginx. If enabling for nginx you need to restart nginx and php-fpm for it to take effect.
[xdebug]
xdebug.remote_autostart=1
xdebug.profiler_enable=1
xdebug.profiler_append=0
xdebug.profiler_output_dir ="/vagrant/web/app/plugins/agreable-catfish-importer-plugin/testing"
xdebug.profiler_output_name = "callgrind.out.%t-%s"
; For extra points you can also link xdebug with Atom, Sublime Text or NetBeans IDEs