I was trying what extensions are for Debug Bar and the Debug Bar Slow Actions thanks to Konstantin Kovshenin. The plugin is really a nice alternative for Xdebug/Webgrind, no need to enable xdebug and restart webserver.
Finally finished my first WordPress plugin. With the help of Woocommerce CSV importer I successfully imported 4175 products into WooCommerce and needed to import attributes. WP All Import is a very good paid alternative (tried there awesome demo), but as a newcomer coder I wanted to learn WP so wrote the plugin that imports those attributes.